) considered two-phase (or unsaturated) incompressible flow in a thin, but long, single pore (a thin strip) with a stratified distribution of the two phases and derived an effective model starting from the Navier-Stokes equations. The upscaled model was obtained using the asymptotic homogenization method. It encompasses different regimes associated to the values of the capillary number and viscosity ratio. It also accounts for surface tension variations (Marangoni effects) which may result from the transport of a solute in one of the two phases. The upscaled model was compared to direct numerical simulations of the 2D pore-scale model. Finally, Airiau and Bottaro (2020) used the adjoint homogenization method to shed new light on the derivation of upscaled models for steady and creeping flow of a shear-thinning fluid in homogeneous porous media. These authors derived a Darcy-like model, where the components of the effective permeability tensor were obtained from the solution of an associated boundary-value problem in a periodic unit cell. Due to the dependence of the viscosity on the pore-scale flow, a coupled solution approach was used that translated into a strong anisotropy of the permeability tensor, even in isotropic geometries.

) used an asymptotic analysis to study single-phase inertial flow in the fluidporous boundary. They show that the total inertial work exerted by the fluid over the solid is always positive.

Non-equilibrium modeling for transport in homogeneous and heterogeneous porous media

This research subject comprises stochastic modeling and upscaling of transport processes.

Introduction

Over the past few years, developments in the theory and numerical simulation of transport phenomena in porous media, along with related experimental measurements, have advanced significantly. New technologies are responsible for the development of methods for measuring properties at unprecedented resolution within a porous material; this has also motivated the formulation of new upscaling techniques. These improvements have occurred across a range of scales of interest. Furthermore, the recent advent of machine learning methods applied to characterization and modeling seems to open another area of research that promises to have impact. This was the motivation for the edition of this special issue of Advances in Water Resources with focus on upscaling and characterization of flow and mass transport in porous media systems across several levels of scale. Another motivation for making this special issue came from a Workshop held at the University of Bordeaux during spring of 2019 dedicated to Michel Quintard. Many of the papers presented here deal with subjects related with his scientific contributions. As a matter of fact, some works explicitly acknowledge his scientific career.

The issue consists of 42 scientific papers spanning over a wide variety of applications and produced by many of the leading scientists in the field. The present editorial provides an overview of the contributions contained in this issue. It is organized in nine sections that summarize the different topics covered by all the articles published in this special issue.

Recent progress in upscaling transport phenomena in porous media

Several works were presented that use the homogenization approach in order to derive the corresponding upscaled model, departing from the governing equations at the pore-scale. [START_REF] Iliev | Homogenization approach to the upscaling of a reactive flow through particulate filters with wall integrated catalyst[END_REF] employed a two-step, double-scale homogenization method to provide macroscale models of diffusion-advection with adsorption typically encountered in filtration processes. The focus was laid upon situations for which adsorption strongly dominates diffusive/convective transfer, implying the development of eigenvalue ancillary problems in the course of upscaling. The first homogenization step, yielded a macroscopic model operating at the scale of the washcoat grains (nanoporous materials) embedded in an inert matrix. The second step resulted in a model at the scale of the filter element. The predictive capabilities of the upscaled models were assessed through comparisons with direct numerical simulations. https://doi.org/10.1016/j.advwatres.2021.103886 newly developed multi-domain spatial Markov model to study threedimensional, heterogeneous and variably-saturated porous media in the catchment zone. They found that this new modeling approach improves the mass transport predictions with respect to a single-domain approach. [START_REF] Gouze | Characterization and upscaling of hydrodynamic transport in heterogeneous dual porosity media[END_REF] carried out Lagrangian upscaling of mass transport in dual porous media consisting of mobile and immobile domains. These authors proposed to separate the advective and diffusive transport processes taking place in each domain. They found good agreement in reproducing two-dimensional time-dependent random walk simulations but the same success was not achieved in three-dimensional structures. On a similar subject, [START_REF] Sherman | Upscaling transport of a sorbing solute in disordered non periodic porous domains[END_REF] studied reactive dispersion within a non-homogeneous, non-periodic porous material. To handle these features, an extended version of the spatial random walk models was proposed using Bernoulli CTRW. The macroscopic model, which is parametrized from subsequent statistics extracted from pore-scale simulations, correctly portrayed the dynamics of the solute plume. This opens a way of including the spatial heterogeneity of Lagrangian statistics in real heterogeneous systems. [START_REF] Tartakovsky | Explaining persistent incomplete mixing in multicomponent reactive transport with Eulerian stochastic model[END_REF] proposed an Eulerian stochastic advection diffusion reaction macroscopic model, in which mechanical and diffusive mixing are conceptually considered as two separate mechanisms, the latter being only responsible for the mixing-controlled reaction. This resulted in an effective dispersion coefficient that is the sum of mechanical dispersion and effective diffusion coefficients. The macroscopic model was successfully compared to experimental results reported in the literature.

Massoudieh and Dentz (2020) followed a more particular approach and proposed to use an integro-differential equation to upscale multispecies and nonlinear reactive transport in heterogeneous porous media. This non-local equation allowed to predict breakthrough curves away from the source on the basis of ergodic cross-sectional velocity distributions and the velocity correlation using a Copula function. The results were validated by comparison with direct numerical simulations. In a similar trend of ideas, [START_REF] Puyguiraud | Effective dispersion coefficients for the upscaling of pore-scale mixing and reaction[END_REF] investigated reactive mixing between two solutes transported in a (2D) porous medium using the concept of dispersive lamella, i.e. , an effective dispersion coefficient that is approximated by the average spatial variance of the solute distribution (assumed to be Gaussian) evolving from a point-like injection. On this basis, the macroscopic spatio-temporal evolution of the reaction product concentration was found to be well-captured as shown by comparison with direct numerical simulations of the pore-scale problem.

Field-scale modeling of flow and transport in porous media

This topic was covered by two works. In the first one, [START_REF] Murad | A three-scale index for flow in karst conduits in carbonate rocks[END_REF] developed a three-scale model for one-phase flow in systems embedding a matrix, conduits and enlarged fractures, as in karstified formations. Starting from the classical compressible version of Darcy's law at the finest scale, a model reduction was applied yielding a 3D (matrix), 2D (fracture) 1D (conduit) coupled system. This model could finally be upscaled once employed on a grid discretizing a fieldscale domain. This yielded the concept of karst-index, similar to that of well-index employed for flow around wells. The second paper is the one from [START_REF] Koohbor | An advanced discrete fracture model for variably saturated flow in fractured porous media[END_REF] , who focused more on simulations and proposed an efficient hybrid numerical scheme that combines finite differences for space discretization and the method of lines for temporal integration to perform the solution of Richards equations in discretely fractured porous media. In order to improve robustness and efficiency of the numerical schemes, these authors proposed to include mass lumping. This solution scheme was applied to study water infiltration in fractured soils and it was validated by comparison with standard numerical techniques.

Current methods for computing effective parameters in porous media

A considerable of attention was brought to this topic. In a quite general framework, Torquato (2020) reported on methods to determine transport coefficients, namely, formation factor, mean survival time, NMR longitudinal relaxation time and principal viscous relaxation time, as well as intrinsic permeability, for hyperuniform and nonhyperuniform structures. Accent was laid upon the relationships between the microsctructure and the coefficients. Questions on how data can be consistently treated to determine effective properties were addressed by several authors. For instance, [START_REF] Thovert | On the influence of boundary conditions when determining transport coefficients from digital images of heterogeneous media[END_REF] analyzed the impact of boundary conditions in the computation of the effective coefficient related to a diffusive process in heterogeneous porous media. With this analysis, means to assess the level of confidence associated with the prediction of this coefficient were obtained. Criteria to anticipate the risk of serious artifacts were devised as well as ways to limit them. In addition, [START_REF] Azizmohammadi | The impact of stress orientation and fracture roughness on the scale dependency of permeability in naturally fractured rocks[END_REF] proposed a sampling method to determine the representative elementary volume (REV) size in fractured rock environments. These authors determined the values of the components of the permeability tensor and analyzed its anisotropy using multiscale random sampling and upscaling, considering the fluid stress orientation and the fracture roughness. Due to the non-homogeneous nature of the fractures geometry, the permeability tensor was position-dependent and the degree of anisotropy of this tensor changed with the REV size, as expected.

A special focus was laid by [START_REF] Ling | 𝜏-SIMPLE algorithm for the closure problem in homogenization of Stokes flows[END_REF] upon the determination of the permeability tensor resulting from the upscaling of onephase steady incompressible Stokes equations. They proposed a computational algorithm, called 𝜏-SIMPLE, that allows computing this quantity from the solution of the associated closure problem present in the homogenization approach. The idea in their algorithm is to introduce an artificial time scale to satisfy the global constraint in the SIMPLE iteration and it was applied to predict permeability in two-and three-dimensional geometries. As an extension out of the creeping flow regime, Aguilar-Madera et al. ( 2020) carried out the solution of the closure problems associated to inertial flow in homogeneous porous media that lead to the prediction of the intrinsic permeability and Forchheimer tensors using digital images from real systems. The latter was found to exhibit a dependence on the average velocity with an exponent ranging from 1.7 to 4.2 depending on the topology and it was verified to be anisotropic not only in terms of the geometry but also in terms of the flow paths.

Many other works addressed the determination of the effective permeability (or hydraulic conductivity) at large scales, for heterogeneous media. For instance, [START_REF] Bellin | Equivalent and effective conductivities of heterogeneous aquifers for steady source flow, with illustration for hydraulic tomography[END_REF] adopted a stochastic approach to identify parameters and compute the effective conductivity from measured values of the hydraulic head for the case of steady flow from a source. These authors found that the ratio of the equivalent conductivity with respect to the geometric mean corresponds to an harmonic mean near the source. They derived the head variance and the autocorrelation between the head near the source and at arbitrary distances. In the work by [START_REF] Colecchio | On the multiscale characterization of effective hydraulic conductivity in random heterogeneous media: A historical survey and some new perspectives[END_REF] , scale-independent analytical results for the variance of the effective hydraulic conductivity were obtained by means of an energy dissipation formulation. The analysis was performed under steady conditions considering two-dimensional domains for lognormal and binary media, considering an ample range of coarsening scales and heterogeneities. Convergence was found to be slower in the binary case than in the lognormal system. With a similar purpose in mind, [START_REF] Mourlanette | Direct simulation of non-additive properties on unstructured grids[END_REF] developed a method to estimate the effective permeability of a geological heterogeneous formation employing a non-structured grid. The power averaging technique was employed in which the permeability was mapped onto the unstructured mesh and further averaged with a power exponent field calibrated from numerical upscaling experiments. The method, which allows very significant computational speed-up, was consistently compared with a refined conventional approach.

An extension to two-phase flow was considered by [START_REF] Soraganvi | Effective flow and transport properties of heterogeneous unsaturated soils[END_REF] . They investigated the prediction of largescale effective unsaturated conductivity in heterogeneous isotropic or anisotropic porous media. The effective coefficients obtained from numerical simulations on random heterogeneous samples were compared to predictions from stochastic spectral perturbation theory, geometric and harmonic means, and to a probabilistic semi-empirical power average model. The latter was shown to provide satisfactory estimates of the principal components of the unsaturated effective conductivity. The macro dispersion was further analyzed in terms of the effective coefficient and spreading lengths using numerical simulations.

Advanced methods for imaging, segmenting, and characterizing complex porous media

This topic was illustrated by the work of [START_REF] Tinet | Comparison of various 3D pore space reconstruction methods and implications on transport properties of nanoporous rocks[END_REF] who addressed the reconstruction of the pore-space of nanoporous materials (clays). They used two variants of the directional aggregation multiplepoint statistics method from 2D images that could be obtained from FIB-SEM or TEM imaging. The choice of the method was found to be conditioned by the available data. It was shown that the reconstruction consistently provides the means to determine the intrinsic permeability, the effective diffusion and longitudinal dispersion coefficients, a key parameter being the distance between two successive 2D images in the reconstruction process.

Coupled phenomena and multiphase flow in porous media

Many research works were reported in this special issue that contributed to shed light on various aspects related to these topics. A new upscaling approach, called LMDTM and applied to MHD flow in a non-Darcian medium between parallel plates subject to Hall current, was proposed by [START_REF] Ewis | A new approach in differential transformation method with application on MHD flow in non-Darcy medium between porous parallel plates considering hall current[END_REF] . The accuracy of the results was tested by comparisons with finite-differences solutions. The novelty of this approach relies on the fact that solution multiplicity and linearization is avoided. [START_REF] Sweijen | Unsaturated flow in a packing of swelling particles; a grain-scale model[END_REF] investigated the coupled unsaturated flow and deformation of a packed bed of swelling particles using pore-scale simulations of liquid invasion inside the grains. It was shown that the swelling coefficient is a key parameter in the swelling and particles rearrangement that are otherwise controlled by the time scales of unsaturated flow and absorption.

Dissolution mechanisms during saturated or unsaturated flow were investigated at the pore-scale by [START_REF] Esteves | Pore-network modeling of single-phase reactive transport and dissolution pattern evaluation[END_REF] who studied reactive transport by means of pore-network modeling taking into account changes in porosity and permeability due to calcite dissolution reactions at the mineral surface. Still at the pore-scale, [START_REF] Etancelin | Improvement of remeshed Lagrangian methods for the simulation of dissolution processes at pore-scale[END_REF] studied dissolution and diffusive transport processes by coupling a Lagrangian formulation with the superficial velocity used in the volume averaging method. This approach takes advantage of the quality of particle tracking for transport, the quality of particle distributions from remeshing and the computation of diffusion by adaptation of the remeshing kernel. At the Darcy scale, [START_REF] Meng | A multiscale study of density-driven flow with dissolution in porous media[END_REF] investigated 2D density-driven flow with dissolution in porous media, combining a linear stability analysis at the Darcy scale and lattice Boltzmann simulations at the pore-scale. Distinct behaviors were observed that are governed by the interplay between the density contrast between the fluids, the chemical reaction rate and the porosity and permeability evolution due to dissolution.

Two-phase flow is another problem that was extensively addressed in this special issue. [START_REF] Alamooti | Direct numerical simulation of trappedphase recirculation at low capillary number[END_REF] performed pore-scale numerical simulations of two-phase flow in different pore-trapping situ-ations in order to analyze the recirculation in the trapped phase for several displacement scenarios, fluids configurations and dynamic parameters. The contrast between drainage and imbibition mechanisms was highlighted. A new computational method that couples graphical processing units for the lattice Boltzmann method with an upscaling technique was developed by An et al. (2020) . This approach was applied to study two-phase flow at a scale-level of centimeters in three applications involving a sandstone sample. This type of volumetric lattice-Boltzmann technique lead to accurate predictions at a lower computational cost than performing routine lattice-Boltzmann simulations.

With the aim of providing a description of two-phase flow at the Darcy scale, [START_REF] Schreyer | Derivation of generalized Cahn-Hilliard equation for twophase flow in porous media using hybrid mixture theory[END_REF] proposed a macroscopic model using the hybrid mixture theory. The model reveals to be compliant with the existing two-phase Cahn-Hilliard equation, the Korteweg stress tensor, Darcy's law and a generalized form of Richards equation. In addition, macroscopic interfaces could be captured by the model. Considering stratified heterogeneous media, [START_REF] Ghosh | Upscaled equations for twophase flow in highly heterogeneous porous media: varying permeability and porosity[END_REF] studied twophase flow in a porous column with varying porosity and permeability in a periodic manner. The resulting flow equations were derived using the homogenization technique and the model predictions were validated by direct numerical simulations at the pore-scale finding good agreement. In addition, [START_REF] Cheng | Upscaling capillary pressure curves for numerical modeling of gravity-capillary driven flow[END_REF] carried out the upscaling process of capillary pressure curves for situations associated to two-phase flow driven by gravity and capillary forces. These authors proposed an upscaling method that relies on optimization, which yielded Brooks and Corey functions that reproduced microscale results, albeit at a considerable computational cost. [START_REF] Kassa | Impact of time-dependent wettability alteration on the dynamics of capillary pressure[END_REF] derived a dynamic capillary-pressure model for two-phase flow in porous media that takes into account temporal variations in wettability by adding a time-dependent term to the standard capillary pressure function. In this way, the relevance of unsteady wettability for determining the capillary pressure over time scales, that range from months to years, was evidenced. Heterogeneous low-permeability matrix-fracture systems were considered by [START_REF] Wang | A discrete fracture model for twophase flow involving the capillary pressure discontinuities in fractured porous media[END_REF] , who provided a methodology to estimate the fracture-matrix two-phase flux assuming negligible capillary effects in the fracture and using a steady-flow approximation. Comparison with reference solutions proved good agreement, validating the approach.

Finally, a study dedicated to three-phase flow at the Darcy scale was reported by [START_REF] Schäfer | On the prediction of threephase relative permeabilities using two-phase constitutive relationships[END_REF] . They analyzed relative permeabilities using the total differential model and the mechanistic model, both recently reported in the literature, to further carry out comparisons with experimental data. The latter model was found to better predict the mobilities and relative permeabilities, to the cost, however, of requiring some preliminary calibration.

Multiscale experimental analysis in porous media

Two studies of flow in tight connection with experimental measurements were reported. In the work by [START_REF] Omirbekov | Experimental and numerical upscaling of foam flow in highly permeable porous media[END_REF] , foam flow experiments were performed in porous media and a simplified upscaled model was employed to predict the seepage velocity to pressure gradient relationship. Poor agreement was achieved and this was explained by the compressibility of the foam at high pressure and trapping effects at low capillary numbers. In addition, an experimental study of thermal effects on capillary pressure and relative permeability curves during quasi-steady and dynamic two-phase drainage/imbibition processes was reported by [START_REF] Philippe | Experimental study of the temperature effect on two-phase flow properties in highly permeable porous media: application to the remediation of dense nonaqueous phase liquids (DNAPLs) in polluted soil[END_REF] . While barely no effects were observed in the former case, relative permeabilities increase and residual saturation decrease were noticed while increasing the temperature under dynamic conditions. This suggests the importance of flow rate in conjunction to temperature effects for the recovery of heavy DNAPL, for instance.

The use of machine learning and neural networks in representations for parameterization in upscaled models in porous media

This new methodology was addressed in the work by [START_REF] Zhou | Seeing macro-dispersivity from hydraulic conductivity field with convolutional neural network[END_REF] who developed a convolutional neural network approach to correlate the hydraulic conductivity field and the longitudinal macro-dispersivity in heterogeneous porous media. Robustness of the deep learning technique was assessed in the case of moderate heterogeneity, showing the potential efficiency of the method to estimate macroscale dispersion from permeabilty fields.

Information theory as it applies to upscaling and upscaled representations in multiphase porous media

This topic was addressed by two papers. In the work by [START_REF] Dell'oca | Quantification of the information content of Darcy fluxes associated with hydraulic conductivity fields evaluated at diverse scales[END_REF] , information theory was used to evaluate the information shared between the Darcy flux fields and those of the hydraulic conductivity. The latter was treated as a spatial random field. In this way, flow was evaluated over several realizations of hydraulic conductivity subject to uniform mean flow. These authors found consistent trends in the variation of the average information in relation to the lower scale size as well as in the manner of information sharing between pairs and triplets of the Darcy flux components. Finally, [START_REF] Wood | A primer on information processing in upscaling[END_REF] reviewed key concepts of information theory and explored how they can be applied to define a representative volume and also to systematically reduce the amount of information in upscaling processes and applied them to several examples. Among the contributions made by the authors in this work, are the distinction between microscale and macroscale variables, and also between empirical and probabilistic entropy. In addition, they extended the notion of typical sequence by requiring that they are also typical in the probabilistic sense.

Acknowledgments

Guest editors are thankful to Paolo D'Odorico for his valuable help in the preparation and editorial work that resulted in this special issue. Didier Lasseux * I2M, UMR 5295, CNRS, Université Bordeaux, 351, Cours de la Libération, 33405 Talence CEDEX, France Francisco J. Valdés-Parada División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, col. Vicentina, 09340, Mexico Brian D. Wood School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR 97330, USA


Anna-Veera Seppanen
email: anna-veera.seppanen@inserm.fr

Priscille Sauvegrain

Elizabeth S Draper

Liis Toome

Rym El

Stavros Petrou

Henrique Barros

J I Luc

Marina Zimmermann

Jennifer Cuttini

Zeitlin

Anna-Veera Seppänen

Zimmermann

Marina Cuttini

Jennifer Zeitlin

Ships Research

Anna-Veera Seppänen

J Lebeer

I Sarrechia

Van Reempts

E Bruneel

E Cloet

A Oostra

E Ortibus

K Denmark

P Boerch

Estonia Pedersen

H Varendi

M Männamaa

P Y Ancel

A Burguet

P H Jarreau

V Pierrat

A Nuytten

R F Germany

M Maier

B Zemlin

L Misselwitz

Italy Wohlers

I Croci

V Carnielli

G Ancora

G Faldella

F Ferrari

( A The Netherlands

Van Heijst

Koopman-Esseboom Poland

J Gadzinowski

J Mazela

A Montgomery

T Pikuła

) Portugal

C R Costa

Sweden Rodrigues

United Kingdom (ES Draper U Aden

SJ A Fenton

S Mader

N Thiele

Health Economics team (S Petrou J M Pfeil

Inserm Coordination

A M Aubert

C Bonnet

A-V Seppänen

Parents' ratings of post-discharge healthcare for their children born very preterm and their suggestions for improvement: a European cohort study

Parents' ratings of post-discharge healthcare for their children born very preterm and their suggestions for improvement: a European cohort study

Acknowledgement This is a post-peer-preview, pre-copyedit version of an article published in Pediatric

Research. The final authenticate version is available online at: http://dx.doi.org/10.1038/s41390-020-01120-y

Impact Statement

 In a European population-based very preterm birth cohort, parents rated postdischarge healthcare as poor or fair for 14.2% of children, with a wide variation (6.1% to 31.6%) between countries  Dissatisfaction was reported in over one-third of cases when children had health or developmental difficulties, such as epilepsy or cerebral palsy  Parents' free-text suggestions for improving preterm-related post-discharge healthcare were similar across countries; these focused primarily on better communication with parents and better coordination of care  Parents' lived experiences are a valuable resource for understanding where care improvements are needed and should be included in future research

Introduction

Very preterm births (<32 weeks of gestation) represent up to 1.6% of births in high-income countries [START_REF] Delnord | Variations in very preterm birth rates in 30 high-income countries: are valid international comparisons possible using routine data?[END_REF] or up to 2% of births worldwide [START_REF] Blencowe | National, regional, and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications[END_REF]. Although survival for these infants has improved, they remain at increased risk of developing multiple health and developmental problems compared to infants born at term [START_REF] Saigal | An overview of mortality and sequelae of preterm birth from infancy to adulthood[END_REF][START_REF] Synnes | Determinants of developmental outcomes in a very preterm Canadian cohort[END_REF]. As the prognosis for each individual infant is unknown at discharge from hospital, follow-up is essential for the early identification of health needs, the coordination of health services from multiple providers, and for enabling timely intervention [START_REF] Mcmanus | Timing and Intensity of Early Intervention Service Use and Outcomes Among a Safety-Net Population of Children[END_REF].

Parents' engagement is crucial for successful follow-up of preterm infants [START_REF] Little | Understanding Barriers to Early Intervention Services for Preterm Infants: Lessons From Two States[END_REF], but few studies have reported on parents' own evaluations of the post-discharge care offered to their children. Parents may provide important insights for improving healthcare beyond aspects of medical, outcome-related quality [START_REF] Gustavsson | Designing quality of care-contributions from parents: Parents' experiences of care processes in paediatric care and their contribution to improvements of the care process in collaboration with healthcare professionals[END_REF][START_REF] Junewicz | Patient-satisfaction surveys on a scale of 0 to 10: improving health care, or leading it astray?[END_REF], and this knowledge may help to improve service adherence, care delivery [START_REF] Junewicz | Patient-satisfaction surveys on a scale of 0 to 10: improving health care, or leading it astray?[END_REF] and, consequently, health outcomes. Qualitative studies involving parents have suggested that there is room for improvement in the continuity of care for preterm infants [START_REF] Rucci | Measuring parents' perspective on continuity of care in children with special health care needs[END_REF] and that assistance with accessing services or providing comprehensive information to parents may impact on the use of post-discharge services in this population [START_REF] Pritchard | Queensland Optimising Preterm Infant Outcomes Group. Parental experiences and preferences which influence subsequent use of post-discharge health services for children born very preterm[END_REF]. The use of early intervention services has been shown to improve outcomes in both children [START_REF] Spittle | Early developmental intervention programmes post-hospital discharge to prevent motor and cognitive impairments in preterm infants[END_REF] and parents [START_REF] Benzies | Key components of early intervention programs for preterm infants and their parents: a systematic review and meta-analysis[END_REF] and may be of most benefit to socially deprived families [START_REF] Spittle | The role of social risk in an early preventative care programme for infants born very preterm: a randomized controlled trial[END_REF]. At the same time, unfavorable social factors such as poorer financial resources [START_REF] Ballantyne | Mothers' and health care providers' perspectives of the barriers and facilitators to attendance at Canadian neonatal follow-up programs[END_REF] or lower educational level [START_REF] Callanan | Children followed with difficulty: how do they differ?[END_REF] have been associated with multiple barriers for attending follow-up services [START_REF] Ballantyne | Mothers' and health care providers' perspectives of the barriers and facilitators to attendance at Canadian neonatal follow-up programs[END_REF] and follow-up discontinuation [START_REF] Callanan | Children followed with difficulty: how do they differ?[END_REF] for children at risk of developmental problems and morbidities.

Although parents are frequently involved in evaluating specific healthcare services or units [START_REF] Butt | Parents' perceptions of ambulatory neonatal follow-up programs[END_REF][START_REF] Hagen | Parental satisfaction with neonatal intensive care units: a quantitative cross-sectional study[END_REF], pediatric specialties [START_REF] Mcintyre | Examining services for young children with autism spectrum disorder: Parent satisfaction and predictors of service utilization[END_REF] or aspects of care [START_REF] Rucci | Measuring parents' perspective on continuity of care in children with special health care needs[END_REF], there have been no large scale or international evaluations of post-discharge care involving parents of children born very preterm. The main aims of this study were to assess parents' ratings of their children's prematurity-related care from discharge from neonatal care until five years of age, in a large cohort from 19 regions in 11 European countries, by sociodemographic characteristics and child health outcomes. In addition, we aimed to provide a thematic synthesis of parents' suggestions on how healthcare can be improved.

Method

Data sources

The data were collected for the Screening to improve Health In very Preterm infantS (SHIPS) study, which followed up the area-based EPICE cohort of infants born before 32 weeks' gestation over 12 months in 2011-2012 [START_REF] Zeitlin | Cohort profile: Effective Perinatal Intensive Care in Europe (EPICE) very preterm birth cohort[END_REF][START_REF] Zeitlin | Use of evidence based practices to improve survival without severe morbidity for very preterm infants: results from the EPICE population based cohort[END_REF], in all maternity units of

Study population

At baseline, the cohort included 7900 live births and 2429 stillbirths and terminations of pregnancies. 6792 infants were discharged alive from the neonatal unit (Supplemental Figure S1 (online)). At five years, 6759 children were alive, of whom parents of 3687 (54.5%) children participated in the follow-up and 3635 (53.8%) returned a questionnaire [START_REF] Zeitlin | Cohort profile: Effective Perinatal Intensive Care in Europe (EPICE) very preterm birth cohort[END_REF].

Data collection

At inclusion, pregnancy and perinatal data were collected from obstetric and neonatal records. At five years of age, health, healthcare and socioeconomic information was collected using parent-report questionnaires that had been pre-tested in all national languages. The questionnaires could be completed at home, in follow-up clinics, online or using paper questionnaires, depending on local study protocols. Questionnaires could be filled in by mothers, fathers or other primary caregivers. They were asked the following question: "How would you describe the healthcare your child has received related to his or her preterm birth after being discharged from the neonatal unit; excellent, good, fair, poor, or has not received any healthcare related to very preterm birth?". The parents were also asked to provide suggestions for how healthcare for very preterm children can be improved, as free-text responses.

Data analysis

Proportions of poor to fair ratings (considered to represent dissatisfaction) were described To obtain adjusted risk ratios for dissatisfaction with healthcare services, we used three multilevel generalized linear regression models with a log link, Poisson distribution and a robust variance estimator [START_REF] Cummings | Methods for estimating adjusted risk ratios[END_REF], with two levels to account for correlation between siblings: one including sociodemographic variables and country only, and two adding either parentrated health and developmental problems or diagnosed developmental or neurosensory difficulties. We did not run a model with all variables due to collinearity between parentreported health status and clinical diagnoses. The covariates were selected based on the scientific literature and bivariate analyses, including variables that were related to parental ratings with a p-value <0.2. We used the sample average as the reference for presenting the country risk ratios for poor/fair ratings. In sensitivity analyses, regression models were [START_REF] Delnord | Variations in very preterm birth rates in 30 high-income countries: are valid international comparisons possible using routine data?[END_REF] adjusted for all covariates without selection based on a p-value cut-off and (2) restricted to cases where the questionnaire was answered by mothers only.

Non-response and missing data

The response rate varied depending on the country (53.8% overall, range 29.3 to 96.4%); non-responders in the cohort were more likely to be younger, foreign-born mothers and have a lower educational level, as detailed elsewhere [START_REF] Zeitlin | Cohort profile: Effective Perinatal Intensive Care in Europe (EPICE) very preterm birth cohort[END_REF]. To take into consideration potential attrition bias, we generated inverse probability weights based on characteristics of non-responders available at baseline and at the two-year follow-up, after multiple imputation of missing values [START_REF] Seaman | Combining multiple imputation and inverse-probability weighting[END_REF], following methods previously used in this cohort [START_REF] Bonnet | Low breastfeeding continuation to 6 months for very preterm infants: A European multiregional cohort study[END_REF].

This approach gives a higher weight to children with characteristics that are underrepresented because of non-response. First, twenty imputations using multiple chained equations were performed to impute missing values for the variables used for predicting the inverse probability weights. Data were assumed to be missing at random. All variables associated with loss to follow-up were included in the regression: gestational age in completed weeks, Apgar score (<7), use of continuous positive airway pressure (CPAP), use of mechanical ventilation, use of prophylactic surfactant within two hours after birth, birth in level 3 unit, inborn status (no transfer within 48h of birth), SGA, any CA (severe or non-severe vs none), BPD, any severe morbidity at discharge (IVH or cPVL, ROP or NEC), surgery (for patent ductus arteriosus, CA, NEC or other reasons), infant received human milk at discharge, mode of delivery (vaginal/instrumental vs caesarean), previous caesarean section, parity at delivery, antepartum hemorrhage after week 20, premature rupture of membranes (>12h), multiplicity, mother's age at delivery, mother's country of birth, mother's educational level, gross motor impairment at 2 years corrected age [START_REF] Johnson | Neurodevelopmental outcomes following late and moderate prematurity: a population-based cohort study[END_REF] and cognitive delay at 2 years corrected age [START_REF] Johnson | Neurodevelopmental outcomes following late and moderate prematurity: a population-based cohort study[END_REF] and study region. The weights were estimated on the total sample of infants eligible for follow-up at 5 years. All proportions in the tables are derived from the weighted sample and all models were run with weights. In sensitivity analyses, we ran models truncating weight values at the 95 th percentile to assess whether the results were affected by the extremes of the weight distribution.

Missing data were not frequent among responders: 2.7% of healthcare ratings were missing and the proportion of missing data varied between 0.3% (maternal age) and 5.3% (country of origin) for co-variables.

Analysis of free-text responses

Free-text responses were explored using thematic analysis. We used an iterative process for the translation of responses and initial coding into keywords and subthemes. The approximately 1300 free-text responses were first automatically translated using Google Translate. Tables including the original juxtaposed with the automatically translated text were used for a first coding of keywords and preliminary themes by the first author. In this step, specific ambiguities in the translations or where multiple interpretations were possible were highlighted. These tables were then sent to the country teams who reviewed the translations and key words. The focus of this step was to ensure that the text was correctly translated and that these translations, as well as the keywords, reflected the original content.

As it was not possible to return questionnaires to the responders for clarifications, responses that could not be interpreted after review, due to poor wording or lack of detail, were removed. After this step, keywords were coded into themes and subthemes by the first author, which were reviewed and validated by a qualitative researcher (PS); a random sample of the responses were double-coded by PS and divergences were discussed with the first author until consensus was reached. Responses that contained more than one suggestion were coded into several themes and duplicate responses for multiple siblings were removed. Themes and subthemes were summarized and described by country and healthcare ratings. Citations were extracted to illustrate the most common subthemes, while ensuring the confidentiality of the responder. The citations selected for presentation in the manuscript were reviewed again by country team members to ensure the precision of the translation.

All data analyses were carried out with STATA 14.0 (Stata Corp., College Station, TX, USA) and Excel 2013.

Results

Questionnaires were returned for 3635 children; by mothers (83%), fathers (15%) and other caretakers, such as grandparents (1.4%), all hereafter referred to as parents. Parents reported that 92.8% of the children had received post-discharge care for their prematurity.

For 14.2% of these children, parents judged the care to be poor or fair, but this varied from 6.1% in France to 31.6% in Denmark. (Table 1). Parents expressed more dissatisfaction with post-discharge care when maternal educational level was higher and when mothers were native-born or born outside Europe compared to mothers born elsewhere in Europe (Table 2). Proportions of poor/fair ratings were higher for children with parent-rated health or developmental problems, diagnosed cerebral palsy or epilepsy, or moderate to severe vision or hearing problem at five years of age.

Higher maternal educational level, being native-born and child health and developmental difficulties remained associated with poor/fair ratings in the adjusted analyses (Table 3). Parents also frequently suggested psychological or emotional support for the parents themselves as part of the long-term follow-up after discharge. They expressed a feeling of being left alone to cope with the trauma of very preterm birth, and the burden of taking care of their child after discharge, without sufficient psychological support for both parents.

"I, as a mother, would have wished for better support after discharge. After the hospital stay, you are left alone with your worries and fears". -Parent, Germany (care rating: Excellent)

"Making room for parents too, because also the motherhood was premature." -Parent, Italy (care rating: Fair)

Subthemes were similar across countries (not shown), and similarly ranked for parents who rated the healthcare as poor or fair and those who rated healthcare as good or excellent.

Discussion

Overall, 14.2% of the children in our study received healthcare that their parents rated as poor or fair, with variation between 6.1% and 31.6% by country. However, dissatisfaction was significantly higher for children with health or developmental problems; up to over one-third when children had a diagnosis of cerebral palsy or epilepsy or when parents rated their children's health as poor or fair. Dissatisfaction with post-discharge care was more frequent among mothers with higher educational status. Thematic analysis of 971 parental responses identified four themes and 25 subthemes about how healthcare could be improved, which were largely similar across countries.

The strengths of this study include its population-based design, geographic diversity, large sample size and the use of a standardized, pre-tested questionnaire. A strength, but also a limitation of the study is the wide definition of post-discharge healthcare covering the period between NICU discharge and five years of age. As follow-up programs and health services vary across countries in terms of availability, content and duration, our questionnaire intentionally referred to a large range of services over a long period of time.

Thus, we are able to measure overall perceptions with how very preterm birth is managed in the long term across countries, but we cannot know if parents referred to specific care aspects in their ratings (medical quality, screening, interventions etc.), unless parents specified the service or time period in the free-text answers. The free-text question intentionally leads parents towards more negative experiences, as it focused on aspects requiring improvement in care. However, the long time period may lead parents to refer care ratings either to more recent care, or care related to more difficult and stressful experiences, which may have happened around NICU discharge and in early childhood when medical follow-up is more intense. In the latter case, the ratings may be more negative than if the question had covered a more proximate period. Unfortunately, we did not have data on the characteristics of services received nor objective measures of the quality of services, such as waiting times or service availability, to contrast with parental perceptions.

Another potential limitation relates to the multilingual nature of our sample, in particular when interpreting the free-text responses. When translation is part of the research process, it inevitably involves a degree of interpretation [START_REF] Larkin | Multilingual translation issues in qualitative research: reflections on a metaphorical process[END_REF], and may increase the risk of misinterpretation of answers [START_REF] Esposito | From meaning to meaning: the influence of translation techniques on non-English focus group research[END_REF]. To minimize this risk, we used an iterative process for the translation and interpretation using automatic translation, followed by coding of keywords and finally a review of translation accuracy and interpretation by researchers in each of the study countries. A final limitation was the potential for bias linked to nonresponse, which was 45.5% for the overall sample and higher in some countries [START_REF] Zeitlin | Cohort profile: Effective Perinatal Intensive Care in Europe (EPICE) very preterm birth cohort[END_REF]. Loss to follow-up is a challenge in longitudinal cohort studies [START_REF] Macbean | Participant retention in follow-up studies of prematurely born children[END_REF], especially those with population-based designs, and can be related to characteristics that may affect healthcare perceptions. We used inverse probability weights to adjust for attrition bias. Reassuringly, results based on the unweighted and weighted analyses were similar, but slightly increased the association between mother's educational level and dissatisfaction as well as perinatal health and dissatisfaction. Previous studies in this cohort have shown that the association between sociodemographic or perinatal factors and health-related outcomes may be accentuated when using these weights [START_REF] Sentenac | Maternal education and language development at 2 years corrected age in children born very preterm: results from a European populationbased cohort study[END_REF], as increased loss to follow-up in socially disadvantaged groups is taken into account.

The proportion of poor/fair ratings varied widely across countries. The study countries differ on several structural aspects that may have contributed to these differences, but that we were not able to measure, such as the organization of primary care [START_REF]State of health in the EU: Companion report 2017[END_REF], level of integrated care in the case of multi-morbidity [START_REF]State of health in the EU: Companion report 2017[END_REF], patients' ability to pay for out of pocketcosts [START_REF] Stepurko | Overall satisfaction of health care users with the quality of and access to health care services: a cross-sectional study in six Central and Eastern European countries[END_REF], and the state's involvement in the healthcare system [START_REF] Wendt | How Do Europeans Perceive Their Healthcare System? Patterns of Satisfaction and Preference for State Involvement in the Field of Healthcare[END_REF]. Furthermore, followup and subsequent care are likely to have been organized very differently across the regions, including access to specialists [START_REF] Seppanen | Specialist health care services use in a European cohort of infants born very preterm[END_REF], as no international standards for follow-up existed at the time. Follow-up programs aim to facilitate care coordination and timely intervention, and might in its absence have contributed to differences in overall satisfaction.

Our study was not designed to link parental perceptions to specific health system features and this remains an area for further research. Differences in ratings could also be related to factors unrelated to the healthcare system. Research on adult patients has proposed that care satisfaction is to a large extent influenced by individual factors such as personality, expectations about healthcare and health status [START_REF] Bleich | How does satisfaction with the healthcare system relate to patient experience?[END_REF]. Patient expectations, in turn, have been associated with several characteristics, including patient age and educational level [START_REF] Bleich | How does satisfaction with the healthcare system relate to patient experience?[END_REF][START_REF] Galle | Expectations and satisfaction with antenatal care among pregnant women with a focus on vulnerable groups: a descriptive study in Ghent[END_REF], which could explain the association between parents' educational status and dissatisfaction in our study. Unknown broader societal factors (34) may explain the differences in ratings that remained across countries after adjusting for child health and parent sociodemographic factors. The subjectivity of the satisfaction measure in our study may accentuate the impact of individual and social factors [START_REF] De Silva | A framework for measuring responsiveness[END_REF], which involve expectations and for which there is no common base level [START_REF] De Silva | A framework for measuring responsiveness[END_REF], as well as different levels of "tolerance" towards service quality, which may depend on the general standard of living in the country [START_REF] De Silva | A framework for measuring responsiveness[END_REF]. This may partly explain the differences in ratings for native, European and non-European-born mothers. Finally, the inclination to express dissatisfaction or complaints may also be cultural [START_REF] Kowalewski | Dissatisfied and Critical Citizens: the Political Effect of Complaining[END_REF] and influence levels of dissatisfaction across countries, but there is, to our knowledge, little evidence on the impact of culture on care perceptions across Europe. The unexplained differences in parents' perceptions may partly mean that care satisfaction represents something different in each country [START_REF] Papanicolas | An analysis of survey data from eleven countries finds that 'satisfaction' with health system performance means many things[END_REF].

The parents' suggestions concerning how healthcare could be improved were predominantly the same across countries. The suggestions were mainly organizational (follow-up coordination, provider training, access to services and timeliness), but the most frequently mentioned subtheme concerned interpersonal aspects (healthcare-provider communication and relationship with parents). Similar themes have been found in other studies [START_REF] Gustavsson | Designing quality of care-contributions from parents: Parents' experiences of care processes in paediatric care and their contribution to improvements of the care process in collaboration with healthcare professionals[END_REF][START_REF] Rucci | Measuring parents' perspective on continuity of care in children with special health care needs[END_REF][START_REF] Pritchard | Queensland Optimising Preterm Infant Outcomes Group. Parental experiences and preferences which influence subsequent use of post-discharge health services for children born very preterm[END_REF][START_REF] Butt | Parents' perceptions of ambulatory neonatal follow-up programs[END_REF][START_REF] Butt | Development and evaluation of an instrument to measure parental satisfaction with quality of care in neonatal follow-up[END_REF][START_REF] Tran | Patients' perspective on how to improve the care of people with chronic conditions in France: a citizen science study within the ComPaRe e-cohort[END_REF], suggesting that healthcare providers may be subject to similar shortcomings regardless of follow-up content and healthcare context. Of note was that many parents had suggestions for improving healthcare despite rating their care as good or excellent, and these were largely similar to parents expressing dissatisfaction. This apparently paradoxical result suggests that even parents who are satisfied with their care in general experience difficulties with care coordination or have unsatisfactory interactions with providers.

Parents of children with health or developmental problems were less satisfied with healthcare, but few suggestions centered on health outcomes, medical quality or technical aspects of care. Other studies have found that dissatisfaction with healthcare services does not necessarily reflect poor medical quality of care [START_REF] Gustavsson | Designing quality of care-contributions from parents: Parents' experiences of care processes in paediatric care and their contribution to improvements of the care process in collaboration with healthcare professionals[END_REF][START_REF] Monier | Fetal and neonatal outcomes of preterm infants born before 32 weeks of gestation according to antenatal vs postnatal assessments of restricted growth[END_REF], but rather poor communication, especially when patients have major disabilities [START_REF] Chang | Patients' global ratings of their health care are not associated with the technical quality of their care[END_REF] or complex healthcare needs [START_REF] Junewicz | Patient-satisfaction surveys on a scale of 0 to 10: improving health care, or leading it astray?[END_REF].

Additionally, poor organization of healthcare may become more apparent for parents whose children require complex multidisciplinary care compared to those with less complex health problems, not seeking healthcare to the same extent. It is also possible that dissatisfaction with health services has an impact on the further use of follow-up and health services, such as change of care provider, seeking care in the private sector, or discontinuing follow-up. We do not have data on unmet service need, which is particularly difficult to define in our European cohort because of differences in health care systems and this remains an area for further investigation. Our results are consistent with those from the Models of Child Health Appraised (MOCHA) study, which showed that European countries are failing to manage complex healthcare needs in the general pediatric population, with no policies for care coordination and care planning after discharge [START_REF] Brenner | Management and integration of care for children living with complex care needs at the acute-community interface in Europe[END_REF].

The lack of integrated healthcare systems for complex care manifests as a lack of multidisciplinary care and inconsistent healthcare provision depending on where care is sought, and may ultimately negatively affect quality of care and health outcomes [START_REF] Brenner | Children's complex care needs: a systematic concept analysis of multidisciplinary language[END_REF]. The parents' suggestions in our study coincide with policy improvements currently being recommended for the follow-up of preterm births, such as multidisciplinary follow-up [START_REF] Efcni | European Standards of Care for Newborn Health: Coordination and integration of care after discharge home[END_REF], follow-up until school age [START_REF] Efcni | European Standards of Care for Newborn Health: Meeting special needs at school. (European Foundation for the Care of Newborn Infants[END_REF] and parent support [START_REF] Efcni | European Standards of Care for Newborn Health: Parental mental health[END_REF]. Further improvements based on parents' lived experiences should be considered in policy strategies.

Over one in ten children born very preterm received post-discharge care that their parents rated as poor or fair, with the highest rates for children who are most reliant on health services. Many parents provided suggestions for improving care, which centered on common themes, despite the wide geographic heterogeneity in ratings. Parents constitute a valuable resource for researchers and policy makers seeking to improve healthcare and for understanding failures in the healthcare system.

TABLES AND FIGURES

Table 4 .

 4 Among the parents who provided free-text responses, 956 also rated the post-discharge care; 25.7% (n=246) rated the care as poor or fair and 74.3% (n=710) as good or excellent (not shown).The most frequent theme was I. Coordination of follow-up and healthcare, with Improving care coordination as the most common subtheme. Parents reported a lack of coordination, having to take responsibility for the organization of healthcare and identification of the appropriate healthcare providers for their child, which was described as an exhausting, stressful, time consuming or difficult task. Some parents experienced having numerous appointments with poor continuity of care and lack of communication between multiple healthcare providers, or asked for a reference person to coordinate care or follow-up. Unfortunately, help for premature babies is only available in larger cities. We live in the countryside and have limited access to all specialists. A visit to a specialist is associated with an additional trip, and I do not always have a transport andThe second most frequent theme was II. Follow-up type and content. Two common suggestions included having more frequent or longer follow-up. The reasons included

	Significant differences in risk ratios persisted across countries after adjustment, despite
	slight changes in point estimates. Incorporating remaining covariates (mother's age, parity,
	multiple birth and asthma diagnosis, p-value>0.2) in our sensitivity analysis did not change
	these associations (data not shown). Sensitivity analysis with only mothers as responders
	showed slightly higher rates of dissatisfaction (15.0% instead of 14.2%), but did not change

the results from the main models (data not shown). Differences between weighted and unweighted proportions of poor and fair ratings were minimal: 13.5% [95% CI

12.3-14.7]

versus 14.2% [95% CI 12.9-15.6] overall (see Supplemental Table

S1

(online) for unweighted proportions by country) and associations with other co-variables in unweighted and weighted models were similar (Supplemental Table

S2

(online)), but slightly increased the association between mother's educational level and dissatisfaction as well as perinatal health and dissatisfaction. Sensitivity analyses truncating weights at the 95 th percentile (n=52 at weight=4.24) did not affect results. See Supplemental Table

S2

(online) for models (Model III) with and without truncated weights, compared to unweighted models.

"Big disappointment that no one has overall responsibility for follow-up. Our daughter has many doctor visits at three different hospitals. Countless visits could have been avoided if someone had an overview of the situation." -Parent, Sweden (care rating: Poor)

Other reoccurring subthemes in this category included the need for further training of generalists and nurses (especially health visitors and Child Healthcare Centre nurses) on preterm birth, having more equitable access to follow-up and services, and reducing waiting times on waiting lists, especially for visits to specialists, and queuing in the waiting rooms.

Thus, more knowledge/education to Child Health Centre and preschool staff." -Parent, Sweden (care rating: Excellent) "reassuring parents that the child was reaching important developmental milestones, to know whether the child was ready for school and/or needed school support. A few parents felt that follow-up was unnecessary when their child was doing well.

"There should be a follow-up when the children reach school age to see how they are developing and whether they are ready to go to school." -Parent, Denmark (care rating:

Fair)

Improving follow-up with additional examinations or therapies, especially before school start, and following up on other areas apart from physical health, such as emotional and mental health, were two frequent subthemes in this category. to care for a child born very preterm and what to expect regarding the child's long-term health or schooling. Some suggestions concerned interpersonal aspects, such as lack of empathy or listening, or requesting a more humane or positive attitude from healthcare providers.

"It was explained in the neonatal unit that in the future we may come across problems such as learning difficulties, vision, hearing, developmental delay. However, it was never explained if and what services would help overcome any of these problems." -Parent, UK (care rating: Poor)

Table 1 .

 1 Parents' ratings of preterm birth-related healthcare by country, ordered by weighted proportion of poor or fair ratings. How would you describe the healthcare your child has received related to his or her preterm birth, after being discharged from the neonatal unit?

			Excellent		Good		Fair		Poor		Poor or fair
	Country	N a	n	% b	n	% b	n	% b	n	% b	% b
	France	688	343	49.8	303	44.1	40	5.8	2	0.3	6.1
	The Netherlands	138	40	30.7	85	60.2	10	7.1	3	2.1	9.2
	Portugal	409	223	54.6	142	34.9	37	8.9	7	1.7	10.5
	Italy	659	327	47.6	259	41.3	58	8.8	15	2.2	11.1
	Belgium	231	82	36.0	120	52.0	26	10.8	3	1.2	12.0
	Estonia	111	52	46.9	44	39.6	13	11.7	2	1.8	13.5
	Sweden	125	51	42.5	49	39.0	18	13.2	7	5.3	18.5
	UK	376	179	47.8	132	33.0	48	12.9	17	6.3	19.2
	Germany	228	84	37.4	99	42.7	37	16.7	8	3.2	19.9
	Poland	173	26	15.0	103	59.7	34	19.6	10	5.6	25.2
	Denmark	144	45	32.6	52	35.8	37	24.4	10	7.2	31.6
	Total	3282	1452	44.0	1388	41.8	358	11.2	84	3.0	14.2

a Excluding missing values and cases where parents reported 'no care received' b Inverse probability weights have been used to adjust for non-response

Table 2 .

 2 Poor or fair ratings by sociodemographic factors, child health and health service use.

	N	n	Poor or fair ratings % a	p a

a Proportions are calculated using inverse probability weights b Lower: >29 weeks' gestation, not small for gestational age, no severe neonatal morbidities, and no congenital anomaly; Moderate: not classified as higher or lower risk; Higher: <28 weeks' gestation or at least one neonatal morbidity or severe congenital anomaly

Table 3 .

 3 Risk ratios of poor or fair ratings by sociodemographic characteristics and child health and development

					Model II: socio-		Model III: socio-
					demographic		demographic
			Model I:		characteristics and parent-	characteristics, perinatal
			sociodemographic	rated health and	risk, developmental and
	Unadjusted Risk Ratios	characteristics	development		neurosensory difficulties
	RR	[95% CI]	a RR	[95% CI]	a RR	[95% CI]	a RR	[95% CI]

Offer parent follow-up and psychological or emotional support

  Non-responders include children for whom parents did not consent to follow-up, who were lost to follow-up or for whom a questionnaire was not returned b Calculated over children alive at five year

	Supplemental Figure S1. Flowchart
	Supplemental
			All very preterm births
			10329
			Stillbirth or termination of
				pregnancy
				2429
			Live births
			7900
			Deceased before discharge
				1108
			Alive at discharge
			6792
				Deceased
				31
			Alive at 2
			6761
				Non-responders
				2336
			Responders at 2
			4425
				Deceased	75	5	4	7
			Offer practical support to parents	2	33	13
	Macro-social context	(44)	Facilitate parents' peer-to-peer communication Train school staff about prematurity Increase length of parental leave Offer school support for child Invest in research on prematurity or related healthcare Alive at 5 6759 Non-responders a 9 14 9 8 5 3072 (45.5%) b Increase healthcare investment 5 Improve media coverage of premature birth 3 Responders at 5 3687 (54.5%) b participants;	20 19 21 22 23 24 25
			3635 (53.8%) b returned questionnaires

a

Table S1 .

 S1 Parents' ratings of preterm birth-related healthcare by country, ordered by unweighted proportion of poor or fair ratings a Excluding missing values and cases where parents reported 'no care received' How would you describe the healthcare your child has received related to his or her preterm birth, after being discharged from the neonatal unit?

			Excellent	Good		Fair		Poor		Poor or fair
	Country	N a	n	%	n	%	n	%	n	%	%
	France	688	343	49.9	303	44.0	40	5.8	2	0.3	6.1
	The Netherlands	138	40	29.0	85	61.6	10	7.3	3	2.2	9.4
	Portugal	409	223	54.5	142	34.7	37	9.1	7	1.7	10.8
	Italy	659	327	49.6	259	39.3	58	8.8	15	2.3	11.1
	Belgium	231	82	35.5	120	52.0	26	11.3	3	1.3	12.6
	Estonia	111	52	46.9	44	39.6	13	11.7	2	1.8	13.5
	UK	376	179	47.6	132	35.1	48	12.8	17	4.5	17.3
	Germany	228	84	36.8	99	43.4	37	16.2	8	3.5	19.7
	Sweden	125	51	40.8	49	39.2	18	14.4	7	5.6	20.0
	Poland	173	26	15.0	103	59.5	34	19.7	10	5.8	25.4
	Denmark	144	45	31.3	52	36.1	37	25.7	10	6.9	32.6
	Total	3282	1452	44.2	1388	42.3	358	10.9	84	2.6	13.5

Author contributions

AVS, ESD, LT, RER, SP, HP, MC, JZ and the SHIPS Research Group made substantial contributions to conception and design and acquisition of data. AVS, PS and JZ analyzed the data. AVS, PS, ESD, LT, RER, SP, HP, LJZ, MC and JZ contributed to interpretation of data, drafting the article, revising it critically for important intellectual content, and approved the final version to be published. Members of the SHIPS research group approved the final version to be published.

Statement of financial support

The research received funding from the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No 633724. Anna-Veera Seppänen has a doctoral contract funded by Sorbonne Université Collège Doctoral, Paris, France.

Disclosure

No conflict of interest declared.

Category of study

Population study

Patient consent

Ethics approvals and parental consent were obtained according to national legislation in each country before data collection