Introducción. La pandemia por coronavirus 2019 (COVID-19) se ha extendido en más de 100 países. La información específica sobre su comportamiento en el embarazo y parto sigue siendo limitada. Objetivo. Describir las características materno perinatales de pacientes gestantes con COVID-19 en un hospital terciario. Métodos. Estudio descriptivo. Se seleccionó todas las gestantes hospitalizadas por el servicio de emergencia de gineco-obstetricia entre el 24 de marzo y el 07 de mayo del 2020 y que tuvieron diagnóstico de infección por SARS-CoV-2, mediante la prueba rápida o la prueba RT-PCR. Se revisó la historia clínica y registros hospitalarios buscando variables sociodemográficas, antecedentes, manifestaciones clínicas, serología materna, complicaciones obstétricas, vía de parto y aspectos perinatales. Resultados. Se encontró 41 casos de pacientes con diagnóstico de SARS-CoV-2. Un 9,2% tuvo resultado de prueba rápida positiva, Los síntomas más comunes fueron tos en 84,6%, fiebre en 76,9% y dolor de garganta en 61,5%. Un 68.2% estuvo asintomática, 19,5% tuvo enfermedad leve y 7,3% moderada. Dos casos de neumonía severa requirieron ventilación no invasiva. No se registró muerte materna. 21,7% de los partos fue vía vaginal y 78,3% por cesárea. Hubo un caso de neonato por parto vaginal con PCR positivo al octavo día de vida. Conclusiones. Hubo un alto porcentaje de pacientes gestantes PCR positivas asintomáticas. Es necesario implementar el tamizaje universal en parturientas en el protocolo de flujo de gestantes en cada institución. / Introduction: The pandemic of coronavirus disease 2019 (COVID-19) has spread to more than 100 countries. Specific information about its behavior in pregnancy is still limited. Objective: To describe the maternal and perinatal characteristics of pregnant patients infected with COVID-19 and their newborns in a tertiary referral hospital. Methods: Descriptive study. Subjects were all pregnant patients admitted to the OB/ GYN Emergency Department of the Edgardo Rebagliati Martins National Hospital from March 24 to May 7, 2020, who were diagnosed with SARS-CoV-2 infection by rapid test or by RT-PCR test. Medical and hospital records were reviewed to retrieve sociodemographic data, patient’s history, clinical manifestations, maternal serology, obstetric complications, delivery mode and perinatal aspects. Results: 41 patients diagnosed with SARS-CoV-2 were identified. 9.2% of all admissions had a positive rapid test. The most common symptoms were cough in 84.6%, fever in 76.9% and sore throat in 61.5%. 68.2% of the patients were asymptomatic, 19.5% had mild illness and 7.3 %, moderate. 2 cases progressed to severe pneumonia requiring non-invasive ventilation. No maternal deaths were recorded. 21.7% were vaginal deliveries, while 78.3% were C-sections. One baby born in a vaginal delivery had a positive PCR result on day 8. Conclusions: A large percentage of asymptomatic pregnant patients had a positive PCR test. Implementing universal screening among patients in l flow protocol is necessary for all institutions.

Introdução: as gestações gemelares estão associadas a elevadas taxas de morbimortalidade tanto maternas quanto perinatais. Algumas intervenções tem o potencial de reduzir essas cifras, tais como a administração de corticosteroides pré- natal, a idade gestacional (IG) de resolução e a via de parto. Porém, a magnitude com que isso ocorre ainda se mantém incerta. Objetivos: comparar os resultados neonatais das gestações gemelares (GG) com os de gestações únicas (GU), levando-se em consideração características demográficas maternas, aquelas relacionadas à gestação atual, bem como sua idade e forma de resolução. Métodos: trata-se de um estudo caso-controle retrospectivo que incluiu 864 gestantes e seus 1298 filhos (430 únicos e 868 gemelares). As pacientes foram pareadas segundo IG de resolução da gestação, de modo que para cada gestação gemelar foi selecionada uma paciente com gestação única, de mesma IG, no mesmo período. O desfecho primário considerado foi resultado adverso perinatal. Características demográficas maternas, antecedentes obstétricos, intercorrências gestacionais, administração de corticosteroides, via de parto e corionicidade foram avaliados como fatores de risco para índices de Apgar no 1º e 5º minutos, morbidade neonatal composta, óbito fetal, óbito neonatal, hipoglicemia e icterícia neonatal. Resultados: tanto nas gestações únicas como nas gemelares, prematuridade foi fator de risco para todos os resultados adversos neonatais, especialmente em IG< 32 semanas. Sofrimento fetal agudo (SFA) aumentou o risco de Apgar de 1º e 5º minuto<7 nas GU. A corticoindução reduziu o risco de índices de Apgar<7, tanto no 1º como no 5º minuto nas GG e apenas no 1º minuto nas GU. Por outro lado, parto vaginal (PV) reduziu o risco de Apgar<7 no 1º minuto nas GU, mas aumentou o risco para os dois resultados adversos na GG. Esse efeito relacionado ao PV não ocorreu sobre a morbidade composta, mas SFA e a monocorionicidade entre os gemelares aumentou o risco desse resultado. SFA também aumentou o risco de óbito neonatal no grupo de GG. Em ambas as populações de RN, o PV foi protetor contra hipoglicemia neonatal. A monocorionicidade, corticoindução e a prematuridade aumentaram o risco de icterícia nos RN de GG. A ausência de doenças maternas protegeu os RN dos resultados adversos considerados. Conclusões: estratégias que visam reduzir prematuridade, doenças maternas e situações de hipoxemia fetal aguda contribuirão para melhores resultados obstétricos, assim como o uso do corticóide pré-natal, tanto nas GU quanto nas GG. A via de parto adequada na gemelaridade permanece controversa. / Introduction: The twin pregnancies are associated with high rates of morbidity and mortality in both mothers and perinatal deaths. Some interventions have the potential to reduce these figures, such as the administration of corticosteroids prenatal care, gestational age (GA) of resolution and the delivery route. However, the magnitude with which this occurs still remains uncertain. Objectives: To compare the neonatal results of the pregnancies of twins (TP) with those of singleton gestations (SG), taking into account maternal demographic characteristics, those related to the current pregnancy, as well as their age and form of delivery. Methods: This was a retrospective case-control study that included 864 pregnant women and their 1298 children (430 single and 868 twins). The patients were paired according to GA for a resolution of the pregnancy, so that for each twin pregnancy, a patient was selected with single pregnancy, of the same GA, during the same period. The primary outcome was considered perinatal adverse result. Demographic characteristics of the mother, obstetric history, complications of pregnancy, administration of corticosteroids, delivery route and chorionicity were evaluated as risk factors for Apgar scores at 1 and 5 minutes, neonatal morbidity composed, fetal death, neonatal death, hypoglycemia and neonatal jaundice. Results: In both pregnancies, prematurity was a risk factor for all adverse results, especially in GA< 32 weeks. Acute fetal distress (AFD) increased the risk of an Apgar score of 1 and 5 minute<7 in SG. The corticoindution reduced the risk of higher Apgar scores<7, both on the 1st and 5th minute in TP and only in the 1st minute in SG. On the other hand, vaginal delivery (VD) reduced the risk of an Apgar score<7 in the 1st minute in SG, but increased the risk for the two adverse results in TP. This effect is related to the VD did not occur on morbidity composed, but AFD and monochorionicity between the twins increased the risk of that result. AFD also increased the risk of neonatal death in the group of TP. In both populations of newborn (NB), the VD was protective against neonatal hypoglycemia. The monochorionicity, corticoindution and prematurity increased the risk of jaundice in NB of TP. The absence of maternal diseases protected the NB of adverse results considered. Conclusions: Strategies that aim to reduce prematurity, maternal diseases and situations of acute fetal hypoxemia will contribute to better outcomes, as well as the use of corticosteroids antenatal care, both in SG and in TP. The delivery route in multiple births remains controversial.

Introdução: as gestações gemelares estão associadas a elevadas taxas de morbimortalidade tanto maternas quanto perinatais. Algumas intervenções tem o potencial de reduzir essas cifras, tais como a administração de corticosteroides pré- natal, a idade gestacional (IG) de resolução e a via de parto. Porém, a magnitude com que isso ocorre ainda se mantém incerta. Objetivos: comparar os resultados neonatais das gestações gemelares (GG) com os de gestações únicas (GU), levando-se em consideração características demográficas maternas, aquelas relacionadas à gestação atual, bem como sua idade e forma de resolução. Métodos: trata-se de um estudo caso-controle retrospectivo que incluiu 864 gestantes e seus 1298 filhos (430 únicos e 868 gemelares). As pacientes foram pareadas segundo IG de resolução da gestação, de modo que para cada gestação gemelar foi selecionada uma paciente com gestação única, de mesma IG, no mesmo período. O desfecho primário considerado foi resultado adverso perinatal. Características demográficas maternas, antecedentes obstétricos, intercorrências gestacionais, administração de corticosteroides, via de parto e corionicidade foram avaliados como fatores de risco para índices de Apgar no 1º e 5º minutos, morbidade neonatal composta, óbito fetal, óbito neonatal, hipoglicemia e icterícia neonatal. Resultados: tanto nas gestações únicas como nas gemelares, prematuridade foi fator de risco para todos os resultados adversos neonatais, especialmente em IG< 32 semanas. Sofrimento fetal agudo (SFA) aumentou o risco de Apgar de 1º e 5º minuto<7 nas GU. A corticoindução reduziu o risco de índices de Apgar<7, tanto no 1º como no 5º minuto nas GG e apenas no 1º minuto nas GU. Por outro lado, parto vaginal (PV) reduziu o risco de Apgar<7 no 1º minuto nas GU, mas aumentou o risco para os dois resultados adversos na GG. Esse efeito relacionado ao PV não ocorreu sobre a morbidade composta, mas SFA e a monocorionicidade entre os gemelares aumentou o risco desse resultado. SFA também aumentou o risco de óbito neonatal no grupo de GG. Em ambas as populações de RN, o PV foi protetor contra hipoglicemia neonatal. A monocorionicidade, corticoindução e a prematuridade aumentaram o risco de icterícia nos RN de GG. A ausência de doenças maternas protegeu os RN dos resultados adversos considerados. Conclusões: estratégias que visam reduzir prematuridade, doenças maternas e situações de hipoxemia fetal aguda contribuirão para melhores resultados obstétricos, assim como o uso do corticóide pré-natal, tanto nas GU quanto nas GG. A via de parto adequada na gemelaridade permanece controversa. / Introduction: The twin pregnancies are associated with high rates of morbidity and mortality in both mothers and perinatal deaths. Some interventions have the potential to reduce these figures, such as the administration of corticosteroids prenatal care, gestational age (GA) of resolution and the delivery route. However, the magnitude with which this occurs still remains uncertain. Objectives: To compare the neonatal results of the pregnancies of twins (TP) with those of singleton gestations (SG), taking into account maternal demographic characteristics, those related to the current pregnancy, as well as their age and form of delivery. Methods: This was a retrospective case-control study that included 864 pregnant women and their 1298 children (430 single and 868 twins). The patients were paired according to GA for a resolution of the pregnancy, so that for each twin pregnancy, a patient was selected with single pregnancy, of the same GA, during the same period. The primary outcome was considered perinatal adverse result. Demographic characteristics of the mother, obstetric history, complications of pregnancy, administration of corticosteroids, delivery route and chorionicity were evaluated as risk factors for Apgar scores at 1 and 5 minutes, neonatal morbidity composed, fetal death, neonatal death, hypoglycemia and neonatal jaundice. Results: In both pregnancies, prematurity was a risk factor for all adverse results, especially in GA< 32 weeks. Acute fetal distress (AFD) increased the risk of an Apgar score of 1 and 5 minute<7 in SG. The corticoindution reduced the risk of higher Apgar scores<7, both on the 1st and 5th minute in TP and only in the 1st minute in SG. On the other hand, vaginal delivery (VD) reduced the risk of an Apgar score<7 in the 1st minute in SG, but increased the risk for the two adverse results in TP. This effect is related to the VD did not occur on morbidity composed, but AFD and monochorionicity between the twins increased the risk of that result. AFD also increased the risk of neonatal death in the group of TP. In both populations of newborn (NB), the VD was protective against neonatal hypoglycemia. The monochorionicity, corticoindution and prematurity increased the risk of jaundice in NB of TP. The absence of maternal diseases protected the NB of adverse results considered. Conclusions: Strategies that aim to reduce prematurity, maternal diseases and situations of acute fetal hypoxemia will contribute to better outcomes, as well as the use of corticosteroids antenatal care, both in SG and in TP. The delivery route in multiple births remains controversial.

INTRODUÇÃO: Na restrição de crescimento intrauterino, a resposta adaptativa a hipóxia, com priorização do fluxo sanguíneo para órgãos nobres, causa vasoconstricção periférica, com aumento da resistência nas artérias renais. Com isso, o desenvolvimento renal é prejudicado e fetos restritos apresentam volumes renais menores. No entanto, a literatura é escassa em estudos que utilizem a ultrassonografia tridimensional na avaliação renal e não descreve a relação desse possível dano renal com desfechos neonatais adversos. Tal técnica tem sido utilizada para mensurar volumes de órgãos e quantificar fluxos sanguíneos de baixa resistência, podendo ser também aplicada para melhorar a avaliação do volume e vascularização renal na restrição de crescimento. OBJETIVOS: Comparar a razão entre o volume renal total e o peso fetal estimado (VRT/PFE) entre fetos com e sem restrição. Além disso, correlacionar o VRT/PFE com a dopplervelocimetria fetal e os índices de vascularização renal e avaliar a associação dos parâmetros renais com eventos neonatais adversos nos fetos restritos. MÉTODOS: O volume total e a vascularização renal de fetos restritos e normais foram avaliados pela ultrassonografia tridimensional e a técnica VOCAL. Os índices de vascularização renal foram corrigidos pela profundidade renal (IVcp, IVFcp and IFcp). Os testes t para amostras independentes e Mann-Whitney foram utilizados para a comparação entre os grupos. Modelos lineares generalizados foram aplicados para avaliar a associação entre as características renais e os eventos neonatais adversos. RESULTADOS: Setenta e um fetos restritos foram comparados a 194 fetos com crescimento normal. O VRT/PFE foi menor no grupo restrito (p < 0,001). Porém essa razão não se correlacionaou com os parâmetros dopplervelocimétricos, os índices vasculares renais ou qualquer evento neonatal adverso. CONCLUSÃO: A razão entre o volume renal total e o peso fetal estimado tende a diminuir na restrição de crescimento intrauterino / INTRODUCTION: In fetal growth restriction, the adaptive response to hypoxia, with prioritization of blood flow to noble organs, causes peripheral vasoconstriction, such as increased resistance in the renal arteries. Then, renal development is impaired and restricted fetuses have lower renal volumes. However, the literature is scarse in studies using three-dimensional ultrasound in renal assessment and does not describe the relationship of this potential renal damage with adverse neonatal outcomes. That technique has been used to mesure volumes and quantify blood flows of low resistance and could also be applied to improve the evaluation of renal volume and vascularization in fetal growth restriction. OBJECTIVES: To compare the ratio of total renal volume to estimated fetal weight (TRV/EFW) among fetuses with and without grown restriction. Fhurthermore, we aim to correlate TRV/EFW with fetal dopplervelocimetry and renal vascularization indexes and to evaluate the association of renal parameters with adverse neonatal events in restricted fetuses. METHODS: Total renal volume and renal vascularization of restricted and normal fetuses were evaluated by three-dimensional ultrasonography and the VOCAL technique. Renal vascularization indexes were corrected for renal depth (VIcd, VFIcd and FIcd). The t-tests for independent samples and Mann-Whitney test were used for comparisons between groups. Generalized linear models were applied to evaluate the association between renal characteristics and adverse neonatal events. RESULTS: Seventy-one restricted fetuses were compared to 194 normally growing fetuses. The TRV/EFW was lower in the restricted group (p < 0.001). However, this ratio did not correlate with Doppler velocimetric parameters, renal vascular indexes or any adverse neonatal events. CONCLUSION: The ratio of total renal volume to estimated fetal weight tends to decrease in intrauterine growth restriction

INTRODUÇÃO: Na restrição de crescimento intrauterino, a resposta adaptativa a hipóxia, com priorização do fluxo sanguíneo para órgãos nobres, causa vasoconstricção periférica, com aumento da resistência nas artérias renais. Com isso, o desenvolvimento renal é prejudicado e fetos restritos apresentam volumes renais menores. No entanto, a literatura é escassa em estudos que utilizem a ultrassonografia tridimensional na avaliação renal e não descreve a relação desse possível dano renal com desfechos neonatais adversos. Tal técnica tem sido utilizada para mensurar volumes de órgãos e quantificar fluxos sanguíneos de baixa resistência, podendo ser também aplicada para melhorar a avaliação do volume e vascularização renal na restrição de crescimento. OBJETIVOS: Comparar a razão entre o volume renal total e o peso fetal estimado (VRT/PFE) entre fetos com e sem restrição. Além disso, correlacionar o VRT/PFE com a dopplervelocimetria fetal e os índices de vascularização renal e avaliar a associação dos parâmetros renais com eventos neonatais adversos nos fetos restritos. MÉTODOS: O volume total e a vascularização renal de fetos restritos e normais foram avaliados pela ultrassonografia tridimensional e a técnica VOCAL. Os índices de vascularização renal foram corrigidos pela profundidade renal (IVcp, IVFcp and IFcp). Os testes t para amostras independentes e Mann-Whitney foram utilizados para a comparação entre os grupos. Modelos lineares generalizados foram aplicados para avaliar a associação entre as características renais e os eventos neonatais adversos. RESULTADOS: Setenta e um fetos restritos foram comparados a 194 fetos com crescimento normal. O VRT/PFE foi menor no grupo restrito (p < 0,001). Porém essa razão não se correlacionaou com os parâmetros dopplervelocimétricos, os índices vasculares renais ou qualquer evento neonatal adverso. CONCLUSÃO: A razão entre o volume renal total e o peso fetal estimado tende a diminuir na restrição de crescimento intrauterino / INTRODUCTION: In fetal growth restriction, the adaptive response to hypoxia, with prioritization of blood flow to noble organs, causes peripheral vasoconstriction, such as increased resistance in the renal arteries. Then, renal development is impaired and restricted fetuses have lower renal volumes. However, the literature is scarse in studies using three-dimensional ultrasound in renal assessment and does not describe the relationship of this potential renal damage with adverse neonatal outcomes. That technique has been used to mesure volumes and quantify blood flows of low resistance and could also be applied to improve the evaluation of renal volume and vascularization in fetal growth restriction. OBJECTIVES: To compare the ratio of total renal volume to estimated fetal weight (TRV/EFW) among fetuses with and without grown restriction. Fhurthermore, we aim to correlate TRV/EFW with fetal dopplervelocimetry and renal vascularization indexes and to evaluate the association of renal parameters with adverse neonatal events in restricted fetuses. METHODS: Total renal volume and renal vascularization of restricted and normal fetuses were evaluated by three-dimensional ultrasonography and the VOCAL technique. Renal vascularization indexes were corrected for renal depth (VIcd, VFIcd and FIcd). The t-tests for independent samples and Mann-Whitney test were used for comparisons between groups. Generalized linear models were applied to evaluate the association between renal characteristics and adverse neonatal events. RESULTS: Seventy-one restricted fetuses were compared to 194 normally growing fetuses. The TRV/EFW was lower in the restricted group (p < 0.001). However, this ratio did not correlate with Doppler velocimetric parameters, renal vascular indexes or any adverse neonatal events. CONCLUSION: The ratio of total renal volume to estimated fetal weight tends to decrease in intrauterine growth restriction

L’objectif de cette thèse était de mesurer l’association de l’obésité maternelle avec la durée de l’allaitement maternel, au total et exclusif, en prenant en compte les caractéristiques sociodémographiques, périnatales et psychosociales ; puis d’évaluer si l’allaitement était, en France en 2012, associé à une diminution de la rétention du poids maternel dans l’année suivant l’accouchement, en particulier chez les femmes obèses.Les données de la cohorte prospective nationale Epifane ont été utilisées. En 2012, 3368 couples mère-enfant avaient été inclus en France métropolitaine. Le recueil de l’alimentation de l’enfant à la maternité puis à 1, 4, 8 et 12 mois postpartum a permis d’estimer les durées d’allaitement. Les facteurs sociodémographiques et périnataux associés à l’obésité maternelle (Indice de Masse Corporelle (IMC) avant grossesse ≥30 kg/m2) ont été identifiés par un modèle de régression logistique multinomiale. Des régressions de Poisson ont fourni des estimations de l’association entre obésité et durées d’allaitement, exclusif et total. Les associations entre durées d’allaitement et rétention de poids à 4 et 12 mois (définie comme la différence entre le poids maternel à 4 et 12 mois et le poids avant grossesse), ont été estimées par des régressions linéaires. Les facteurs de risque d’une rétention de poids modeste (entre 0,1 et 4,9 kg) ou majeure (≥5 kg) à un an, ont été identifiés par des régressions logistiques multinomialesL’obésité maternelle était associée à un ensemble de caractéristiques sociodémographiques et de complications périnatales, de façon différente selon la parité. Par ailleurs, elle était associée à une durée totale d’allaitement plus courte, comparé à une corpulence normale, indépendamment des caractéristiques sociodémographiques, périnatales, psychosociales, et de la parité. La parité modifiait l’association entre obésité et durée d’allaitement exclusif. Ainsi, chez les primipares, la durée d’allaitement exclusif était comparable chez les femmes obèses et celles de corpulence normale, quel que soit le niveau d’ajustement. Chez les multipares, la relation entre obésité maternelle et durée d’allaitement exclusif réduite observée dans le modèle ajusté sur les caractéristiques sociodémographiques, n’était plus significative lorsque les caractéristiques périnatales et psychosociales étaient ajoutées au modèle.A 4 mois, dans tous les groupes d’IMC avant grossesse, la rétention moyenne de poids postpartum n’était pas différente selon la durée d’allaitement exclusif ou prédominant. Néanmoins, la durée d’allaitement mixte était associée à une augmentation de la rétention de poids à 4 mois, chez les femmes obèses uniquement. A 12 mois, ni la durée d’allaitement exclusif ou prédominant, ni celle d’allaitement mixte n’étaient associées à la rétention de poids. Les risques d’une rétention de poids modeste ou majeure une année après avoir accouché, variaient toutefois selon un ensemble de caractéristiques sociodémographiques et périnatales. La durée totale d’allaitement maternel était plus faible chez les femmes obèses. Par ailleurs, nos travaux ne montrent pas un bénéfice de l’allaitement sur la diminution de la rétention de poids à 4 et 12 mois. Finalement, nos travaux apportent une meilleure compréhension des mécanismes impliqués dans la relation entre obésité et allaitement maternel ; l’identification des facteurs de risque de la rétention de poids ouvre de nombreuses perspectives de recherche. En termes de santé publique, ces travaux réaffirment la nécessité de prendre en compte les facteurs psychosociaux, les caractéristiques sociodémographiques, et les conditions de la grossesse dans la promotion de l’allaitement, notamment exclusif, et dans les actions visant à réduire la rétention de poids postpartum. / The aim of this PhD dissertation was to measure the association of maternal obesity with any breastfeeding (ABF), and exclusive breastfeeding (EBF) durations, taking into account sociodemographic, perinatal and psychosocial factors; and to assess whether in France, in 2012, breasfeeding was associated with a reduction in PPWR during the first year of life, especially among women obese before pregnancy.We used data from the French population-based-birth-cohort Epifane. In 2012, 3,368 mother-infant dyads were included in mainland France. Information concerning infant’s feeding were collected at maternity ward and at 1, 4, 8, and 12 months, and were then used to define breastfeeding durations. Sociodemographic and perinatal factors associated with maternal obesity (Body Mass Index (BMI) before pregnancy ≥30 kg/m2) were identified using a multinomial logistic regression model. Poisson regression models have estimated associations of maternal obesity with ABF and EBF durations. Linear regression models were used to estimate the associations of breastfeeding durations (full breastfeeding (FBF) and partial breastfeeding) with PPWR at 4 and 12 months (defined as the difference between the maternal weight at 4 and 12 months after birth and maternal prepregnancy weight). Risk factors of moderate PPWR (0.1-4.9 kg) and major PPWR (≥5 kg) at 12 months were identified using multinomial logistic regression modelling.Maternal obesity was associated with sociodemographic characteristics and adverse perinatal outcomes. Such patterns varied among primiparous and multiparous women. Furthermore, maternal obesity was associated with a reduced ABF duration, compared to normal-weight, independently of sociodemographic, perinatal and psychosocial factors, and parity. Association of maternal obesity with EBF duration was modified by parity. Among primiparous women, obese women exclusively breastfed as long as normal-weight women, in all adjusted models. Among multiparous women, association between maternal obesity and reduced EBF duration, observed in the crude model and model adjusted on sociodemographic factors, was no more statistically significant when adjusting for perinatal and psychosocial factors.Four months after birth, FBF duration was not associated with PPWR, regardless of prepregnancy BMI class. However, partial breastfeeding duration was associated with an increased PPWR at 4 months among women obese before pregnancy. At 12 months, neither FBF duration nor partial breastfeeding duration was associated with PPWR. Nevertheless, we identified a set of sociodemographic and perinatal risk factors of moderate and major PPWR at 12 months.Maternal obesity was associated with a reduced ABF duration. Furthermore, our work does not confirm the hypothesis of a benefit of breastfeeding durations on PPWR at 4 and 12 months. Finally, our research provides a better understanding of mechanisms involved in the relation between maternal obesity and breastfeeding; the identification of PPWR risk factors opens new prospects of research. In terms of public health, our research reinforces the need to consider sociodemographic, perinatal and psychosocial characterictics of women in the promotion of breastfeeding, especially EBF, and in the interventions aimed at reducing PPWR.