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Effet des vitamines/oméga chez la femme enceinte sur le bébé

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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 11 Juil 2023 17:02

Traduction de l'étude :wink:

L'apport en iode modifie-t-il l'effet de la dysglycémie maternelle sur le poids à la naissance chez les populations présentant une carence en iode légère à modérée ? Une étude de cohorte prospective mère-nouveau-né
par Yaniv S. Ovadia Nutrients 2023, 15(13), 2914 ;

On ne sait pas comment le statut glycémique maternel et le statut iodé maternel influencent le poids à la naissance chez les personnes présentant une carence en iode (DI) légère à modérée. Nous avons étudié l'association entre le poids à la naissance et les niveaux de glucose maternel et l'apport en iode chez les femmes enceintes présentant une DI légère à modérée. Les valeurs de glucose ont été évaluées à l'aide d'un test de provocation au glucose (GCT) et de taux de glucose non à jeun qui ont été déterminés avant l'accouchement ; les statuts en iode des individus ont été évalués à l'aide d'un questionnaire de fréquence alimentaire en iode ; et la thyroglobuline sérique (Tg) et les concentrations d'iode urinaire (UIC) ont été utilisées pour évaluer le statut en iode de chaque groupe. Les anticorps thyroïdiens et les taux de thyroxine libre (FT4) ont été mesurés. Des données obstétricales et anthropométriques ont également été recueillies. Le statut de grande taille pour l'âge gestationnel (LGA) a été prédit à l'aide d'un modèle de risques proportionnels de Cox avec plusieurs facteurs de confusion. Une Tg > 13 g/L était indépendamment associée à l'AGL (risque relatif ajusté = 3,4, IC à 95 % : 1,4–10,2, p = 0,001). L'apport en iode estimé était corrélé au FT4 parmi les participants qui ont déclaré avoir consommé des suppléments contenant de l'iode (ICS) après ajustement pour les facteurs de confusion (β = 0,4, IC à 95 % : 0,0002-0,0008, p = 0,001). Les centiles de poids du nouveau-né étaient inversement corrélés aux valeurs maternelles de FT4 (β = −0,2 IC à 95 % : −0,08–−56,49, p = 0,049).

Nous concluons que dans les régions ID légères à modérées, un statut maternel insuffisant en iode peut augmenter le risque de LGA. Le statut en iode et l'apport de CSI peuvent modifier l'effet de la dysglycémie maternelle sur le poids de la progéniture.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 12 Juil 2023 13:16

Micronutrient supplementation interventions in preconception and pregnant women at increased risk of developing pre-eclampsia: a systematic review and meta-analysis
Sowmiya Gunabalasingam European Journal of Clinical Nutrition volume 77, pages710–730 (2023)

Background
Pre-eclampsia can lead to maternal and neonatal complications and is a common cause of maternal mortality worldwide. This review has examined the effect of micronutrient supplementation interventions in women identified as having a greater risk of developing pre-eclampsia.

Methods
A systematic review was performed using the PRISMA guidelines. The electronic databases MEDLINE, EMBASE and the Cochrane Central Register of Controlled trials were searched for relevant literature and eligible studies identified according to a pre-specified criteria. A meta-analysis of randomised controlled trials (RCTs) was conducted to examine the effect of micronutrient supplementation on pre-eclampsia in high-risk women.

Results
Twenty RCTs were identified and supplementation included vitamin C and E (n = 7), calcium (n = 5), vitamin D (n = 3), folic acid (n = 2), magnesium (n = 1) and multiple micronutrients (n = 2). Sample size and recruitment time point varied across studies and a variety of predictive factors were used to identify participants, with a previous history of pre-eclampsia being the most common. No studies utilised a validated prediction model. There was a reduction in pre-eclampsia with calcium (risk difference, −0.15 (−0.27, −0.03, I2 = 83.4%)), and vitamin D (risk difference, −0.09 (−0.17, −0.02, I2 = 0.0%)) supplementation.

Conclusion
Our findings show a lower rate of pre-eclampsia with calcium and vitamin D, however, conclusions were limited by small sample sizes, methodological variability and heterogeneity between studies. Further higher quality, large-scale RCTs of calcium and vitamin D are warranted. Exploration of interventions at different time points before and during pregnancy as well as those which utilise prediction modelling methodology, would provide greater insight into the efficacy of micronutrient supplementation intervention in the prevention of pre-eclampsia in high-risk women.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 12 Juil 2023 16:55

Traduction de l'étude :wink:

Interventions de supplémentation en micronutriments chez les femmes préconceptionnelles et enceintes présentant un risque accru de développer une prééclampsie : une revue systématique et une méta-analyse
Sowmiya Gunabalasingam Journal européen de nutrition clinique volume 77, pages 710–730 (2023)

Arrière-plan
La pré-éclampsie peut entraîner des complications maternelles et néonatales et est une cause fréquente de mortalité maternelle dans le monde. Cette revue a examiné l'effet des interventions de supplémentation en micronutriments chez les femmes identifiées comme ayant un plus grand risque de développer une pré-éclampsie.

Méthodes
Une revue systématique a été réalisée en utilisant les lignes directrices PRISMA. Les bases de données électroniques MEDLINE, EMBASE et le registre Cochrane des essais contrôlés ont été recherchés pour la littérature pertinente et les études éligibles identifiées selon des critères pré-spécifiés. Une méta-analyse d'essais contrôlés randomisés (ECR) a été menée pour examiner l'effet de la supplémentation en micronutriments sur la pré-éclampsie chez les femmes à haut risque.

Résultats
Vingt ECR ont été identifiés et la supplémentation comprenait la vitamine C et E (n = 7), le calcium (n = 5), la vitamine D (n = 3), l'acide folique (n = 2), le magnésium (n = 1) et plusieurs micronutriments ( n = 2). La taille de l'échantillon et le moment du recrutement variaient d'une étude à l'autre et divers facteurs prédictifs ont été utilisés pour identifier les participantes, les antécédents de prééclampsie étant les plus courants. Aucune étude n'a utilisé un modèle de prédiction validé. Il y avait une réduction de la pré-éclampsie avec le calcium (différence de risque, -0,15 (-0,27, -0,03, I2 = 83,4%)) et la vitamine D (différence de risque, -0,09 (-0,17, -0,02, I2 = 0,0% )) supplémentation.

Conclusion
Nos résultats montrent un taux plus faible de pré-éclampsie avec le calcium et la vitamine D, cependant, les conclusions ont été limitées par la petite taille des échantillons, la variabilité méthodologique et l'hétérogénéité entre les études. D'autres ECR à grande échelle et de meilleure qualité sur le calcium et la vitamine D sont justifiés. L'exploration des interventions à différents moments avant et pendant la grossesse ainsi que celles qui utilisent la méthodologie de modélisation de prédiction, fournirait une meilleure compréhension de l'efficacité de l'intervention de supplémentation en micronutriments dans la prévention de la pré-éclampsie chez les femmes à haut risque.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 15 Juil 2023 11:44

Dietary supplements and vascular function in hypertensive disorders of pregnancy
Andy W C Man Pflügers Archiv - European Journal of Physiology volume 475, pages889–905 (2023)

Hypertensive disorders of pregnancy are complications that can lead to maternal and infant mortality and morbidity. Hypertensive disorders of pregnancy are generally defined as hypertension and may be accompanied by other end organ damages including proteinuria, maternal organ disturbances including renal insufficiency, neurological complications, thrombocytopenia, impaired liver function, or uteroplacental dysfunction such as fetal growth restriction and stillbirth. Although the causes of these hypertensive disorders of pregnancy are multifactorial and elusive, they seem to share some common vascular-related mechanisms, including diseased spiral arteries, placental ischemia, and endothelial dysfunction. Recently, preeclampsia is being considered as a vascular disorder. Unfortunately, due to the complex etiology of preeclampsia and safety concerns on drug usage during pregnancy, there is still no effective pharmacological treatments available for preeclampsia yet. An emerging area of interest in this research field is the potential beneficial effects of dietary intervention on reducing the risk of preeclampsia. Recent studies have been focused on the association between deficiencies or excesses of some nutrients and complications during pregnancy, fetal growth and development, and later risk of cardiovascular and metabolic diseases in the offspring. In this review, we discuss the involvement of placental vascular dysfunction in preeclampsia.

We summarize the current understanding of the association between abnormal placentation and preeclampsia in a vascular perspective. Finally, we evaluate several studied dietary supplementations to prevent and reduce the risk of preeclampsia, targeting placental vascular development and function, leading to improved pregnancy and postnatal outcomes.

L-arginine
As mentioned above, NO is a potent endothelium-derived vasodilator and defective eNOS/NO signaling has been documented in preeclampsia. NO is produced by eNOS which uses L-arginine as substrate. Therefore, the bio-availability of L-arginine is important to maintain the endothelial adaptive regulatory mechanisms for vasodilatation in healthy pregnancy. Arginine is a semi-essential amino acid and the precursor of various biological pathways including the urea cycle and the production of NO and polyamines [149, 150]. Arginine may regulate many metabolic pathways that are crucial to reproduction, growth, and health [151], while the role and functions of NO have been discussed above. It is well documented that the administration of L-arginine improves vascular function in atherosclerosis and peripheral vascular diseases
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 17 Juil 2023 14:49

Traduction de l'étude :wink:

Compléments alimentaires et fonction vasculaire dans les troubles hypertensifs de la grossesse
Andy WC Man Pflügers Archiv - Journal européen de physiologie volume 475, pages 889–905 (2023)

Les troubles hypertensifs de la grossesse sont des complications qui peuvent entraîner une mortalité et une morbidité maternelles et infantiles. Les troubles hypertensifs de la grossesse sont généralement définis comme une hypertension et peuvent s'accompagner d'autres lésions des organes cibles, notamment la protéinurie, des troubles des organes maternels, notamment une insuffisance rénale, des complications neurologiques, une thrombocytopénie, une altération de la fonction hépatique ou un dysfonctionnement utéroplacentaire tel qu'un retard de croissance fœtale et une mortinaissance. Bien que les causes de ces troubles hypertensifs de la grossesse soient multifactorielles et insaisissables, elles semblent partager certains mécanismes vasculaires communs, notamment les artères spiralées malades, l'ischémie placentaire et le dysfonctionnement endothélial. Récemment, la prééclampsie est considérée comme un trouble vasculaire. Malheureusement, en raison de l'étiologie complexe de la prééclampsie et des problèmes de sécurité liés à l'utilisation de médicaments pendant la grossesse, il n'existe toujours pas de traitements pharmacologiques efficaces pour la prééclampsie. Un nouveau domaine d'intérêt dans ce domaine de recherche est les effets bénéfiques potentiels de l'intervention alimentaire sur la réduction du risque de prééclampsie. Des études récentes se sont concentrées sur l'association entre les carences ou les excès de certains nutriments et les complications pendant la grossesse, la croissance et le développement du fœtus, et le risque ultérieur de maladies cardiovasculaires et métaboliques chez la progéniture. Dans cette revue, nous discutons de l'implication du dysfonctionnement vasculaire placentaire dans la prééclampsie.

Nous résumons la compréhension actuelle de l'association entre la placentation anormale et la prééclampsie dans une perspective vasculaire. Enfin, nous évaluons plusieurs compléments alimentaires étudiés pour prévenir et réduire le risque de prééclampsie, ciblant le développement et la fonction vasculaire placentaire, conduisant à une amélioration de la grossesse et des résultats postnatals.

L-arginine
Comme mentionné ci-dessus, le NO est un puissant vasodilatateur dérivé de l'endothélium et une signalisation eNOS/NO défectueuse a été documentée dans la prééclampsie. Le NO est produit par eNOS qui utilise la L-arginine comme substrat. Par conséquent, la biodisponibilité de la L-arginine est importante pour maintenir les mécanismes de régulation adaptatifs endothéliaux pour la vasodilatation au cours d'une grossesse en bonne santé. L'arginine est un acide aminé semi-essentiel et le précurseur de diverses voies biologiques dont le cycle de l'urée et la production de NO et de polyamines [149, 150]. L'arginine peut réguler de nombreuses voies métaboliques cruciales pour la reproduction, la croissance et la santé [151], tandis que le rôle et les fonctions du NO ont été discutés ci-dessus. Il est bien documenté que l'administration de L-arginine améliore la fonction vasculaire dans l'athérosclérose et les maladies vasculaires périphériques
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 19 Juil 2023 12:16

Prenatal delta-9-tetrahydrocannabinol exposure is associated with changes in rhesus macaque DNA methylation enriched for autism genes
Lyndsey E. Shorey-Kendrick, Clinical Epigenetics volume 15, Article number: 104 (2023)

Background
With the growing availability of cannabis and the popularization of additional routes of cannabis use beyond smoking, including edibles, the prevalence of cannabis use in pregnancy is rapidly increasing. However, the potential effects of prenatal cannabis use on fetal developmental programming remain unknown.

Results
We designed this study to determine whether the use of edible cannabis during pregnancy is deleterious to the fetal and placental epigenome. Pregnant rhesus macaques consumed a daily edible containing either delta-9-tetrahydrocannabinol (THC) (2.5 mg/7 kg/day) or placebo. DNA methylation was measured in 5 tissues collected at cesarean delivery (placenta, lung, cerebellum, prefrontal cortex, and right ventricle of the heart) using the Illumina MethylationEPIC platform and filtering for probes previously validated in rhesus macaque. In utero exposure to THC was associated with differential methylation at 581 CpGs, with 573 (98%) identified in placenta. Loci differentially methylated with THC were enriched for candidate autism spectrum disorder (ASD) genes from the Simons Foundation Autism Research Initiative (SFARI) database in all tissues. The placenta demonstrated greatest SFARI gene enrichment, including genes differentially methylated in placentas from a prospective ASD study.

Conclusions
Overall, our findings reveal that prenatal THC exposure alters placental and fetal DNA methylation at genes involved in neurobehavioral development that may influence longer-term offspring outcomes. The data from this study add to the limited existing literature to help guide patient counseling and public health polices focused on prenatal cannabis use in the future.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 20 Juil 2023 16:30

Traduction de l'étude :wink:

L'exposition prénatale au delta-9-tétrahydrocannabinol est associée à des changements dans la méthylation de l'ADN du macaque rhésus enrichi pour les gènes de l'autisme
Lyndsey E. Shorey-Kendrick, Épigénétique clinique volume 15, Numéro d'article : 104 (2023)

Arrière-plan
Avec la disponibilité croissante du cannabis et la vulgarisation d'autres voies de consommation de cannabis au-delà du tabagisme, y compris les produits comestibles, la prévalence de la consommation de cannabis pendant la grossesse augmente rapidement. Cependant, les effets potentiels de la consommation prénatale de cannabis sur la programmation du développement fœtal demeurent inconnus.

Résultats
Nous avons conçu cette étude pour déterminer si l'utilisation de cannabis comestible pendant la grossesse est délétère pour l'épigénome fœtal et placentaire. Des macaques rhésus enceintes consommaient quotidiennement un aliment contenant soit du delta-9-tétrahydrocannabinol (THC) (2,5 mg/7 kg/jour) soit un placebo. La méthylation de l'ADN a été mesurée dans 5 tissus prélevés lors de l'accouchement par césarienne (placenta, poumon, cervelet, cortex préfrontal et ventricule droit du cœur) à l'aide de la plateforme Illumina MethylationEPIC et en filtrant les sondes préalablement validées chez le macaque rhésus. L'exposition in utero au THC a été associée à une méthylation différentielle à 581 CpG, dont 573 (98 %) ont été identifiés dans le placenta. Les loci différentiellement méthylés avec du THC ont été enrichis pour les gènes candidats des troubles du spectre autistique (TSA) de la base de données Simons Foundation Autism Research Initiative (SFARI) dans tous les tissus. Le placenta a démontré le plus grand enrichissement en gènes SFARI, y compris les gènes différentiellement méthylés dans les placentas à partir d'une étude prospective sur les TSA.

conclusion
Dans l'ensemble, nos résultats révèlent que l'exposition prénatale au THC modifie la méthylation de l'ADN placentaire et fœtal au niveau des gènes impliqués dans le développement neurocomportemental qui peuvent influencer les résultats à long terme de la progéniture. Les données de cette étude s'ajoutent à la littérature existante limitée pour aider à guider les conseils aux patients et les politiques de santé publique axées sur la consommation prénatale de cannabis à l'avenir.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 26 Juil 2023 11:25

Maternal vitamin D deficiency and brain functions: a never-ending story
Lidia Saidi Food Funct Issue 14, 2023

A large number of observational studies have highlighted the prevalence rates of vitamin D insufficiency and deficiency in many populations including pregnant women. Vitamin D is well known to have a crucial role in differentiation and proliferation, as well as neurotrophic and neuroprotective actions in the brain. It has been observed that this micronutrient can modulate neurotransmission and synaptic plasticity. Recent results from animal and epidemiological studies indicated that maternal vitamin D deficiency is associated with a wide range of neurobiological diseases including autism, schizophrenia, depression, multiple sclerosis and developmental defects. The aim of this review is to summarize the current state of knowledge on the effect of maternal vitamin D deficiency on brain functions and development.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 26 Juil 2023 13:45

Traduction de l'étude :wink:

Carence maternelle en vitamine D et fonctions cérébrales : une histoire sans fin
Lidia Saidi Fonction alimentaire Numéro 14, 2023

Un grand nombre d'études observationnelles ont mis en évidence les taux de prévalence de l'insuffisance et de la carence en vitamine D dans de nombreuses populations, y compris les femmes enceintes. La vitamine D est bien connue pour avoir un rôle crucial dans la différenciation et la prolifération, ainsi que des actions neurotrophiques et neuroprotectrices dans le cerveau. Il a été observé que ce micronutriment peut moduler la neurotransmission et la plasticité synaptique. Des résultats récents d'études animales et épidémiologiques ont indiqué que la carence maternelle en vitamine D est associée à un large éventail de maladies neurobiologiques, notamment l'autisme, la schizophrénie, la dépression, la sclérose en plaques et des anomalies du développement. L'objectif de cette revue est de résumer l'état actuel des connaissances sur l'effet de la carence maternelle en vitamine D sur les fonctions cérébrales et le développement.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 27 Juil 2023 14:37

Associations between obesity, smoking behaviors, reproductive traits and spontaneous abortion: a univariable and multivariable Mendelian randomization study
Qingyi Wang Front. Endocrinol., 20 July 2023

Background: The correlation between potential risk factors such as obesity (leg fat percentage (left), arm fat percentage (left), waist circumference, body fat percentage, trunk fat percentage), smoking behaviors (past tobacco smoking, smoking initiation, smoking/smokers in household, current tobacco smoking) and reproductive traits (age first had sexual intercourse (AFS), age at menarche (AAM), and age at first birth (AFB)) have been linked to the occurrence of spontaneous abortion (SA). However, the causal associations between these factors and SA remain unclear.

Methods: We conducted univariable and multivariable Mendelian randomization (MR) analyses to evaluate the associations of obesity, smoking behavior and reproductive traits with SA. To select appropriate genetic instruments, we considered those that had reached the genome-wide significance level (P < 5 × 10–8) in their corresponding genome-wide association studies (GWAS) involving a large number of individuals (ranging from 29,346 to 1,232,091). SA was obtained from the FinnGen consortium, which provided summary-level data for 15,073 SA cases and 135,962 non-cases.

Results: Assessed individually using MR, the odds ratios (ORs) of SA were 0.728 (P = 4.3608×10-8), 1.063 (P = 0.0321), 0.926 (P = 9.4205×10-4), 1.141 (P = 7.9882×10-3), 5.154 (P = 0.0420), 1.220 (P = 0.0350), 1.228 (P = 0.0117), 0.795 (P = 0.0056), 1.126 (P = 0.0318), for one standard deviation (SD) increase in AFS, AAM, AFB, smoking initiation, smoking/smokers in household, arm fat percentage (left), leg fat percentage (left), waist circumference and body fat percentage, 0.925 (P = 0.4158) and 1.075 (P = 0.1479) for one SD increase in past tobacco smoking, trunk fat percentage for one SD increase in SA. In multivariable MR (MVMR), only AFS (OR = 0.802; P = 0.0250), smoking initiation (OR = 1.472, P = 0.0258), waist circumference (OR = 0.813, P = 0.0220) and leg fat percentage (left) (OR = 4.446, P = 0.043) retained a robust effect.

Conclusion: Smoking behaviors, reproductive traits and obesity-related anthropometric indicators are potential causal factors for SA. Higher leg fat percentage; smoking initiation; and lower waist circumference and AFS may increase the risk of SA. Understanding the causal relationship for SA may provide more information for SA intervention and prevention strategies.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Diététique » 27 Juil 2023 17:19

Traduction de l'étude :wink:

Associations entre l'obésité, les comportements tabagiques, les traits reproductifs et l'avortement spontané : une étude de randomisation mendélienne univariée et multivariée
Front Qingyi Wang. Endocrinol., 20 juillet 2023

Contexte : La corrélation entre les facteurs de risque potentiels tels que l'obésité (pourcentage de graisse dans les jambes (à gauche), pourcentage de graisse dans les bras (à gauche), tour de taille, pourcentage de graisse corporelle, pourcentage de graisse dans le tronc), les comportements liés au tabagisme (fumer du tabac dans le passé, début du tabagisme, tabagisme/ fumeurs dans le ménage, tabagisme actuel) et les traits de reproduction (âge du premier rapport sexuel (AFS), âge à la ménarche (AAM) et âge à la première naissance (AFB)) ont été liés à la survenue d'avortements spontanés (AS). Cependant, les associations causales entre ces facteurs et l'AS restent floues.

Méthodes : Nous avons effectué des analyses de randomisation mendélienne (RM) univariées et multivariées pour évaluer les associations entre l'obésité, le comportement tabagique et les traits de reproduction avec l'AS. Pour sélectionner les instruments génétiques appropriés, nous avons considéré ceux qui avaient atteint le niveau de signification à l'échelle du génome (P < 5 × 10–8) dans leurs études d'association à l'échelle du génome (GWAS) correspondantes impliquant un grand nombre d'individus (allant de 29 346 à 1 232 091 ). L'AS a été obtenue auprès du consortium FinnGen, qui a fourni des données sommaires pour 15 073 cas d'AS et 135 962 non-cas.

Résultats : Évalués individuellement à l'aide de la RM, les rapports de cotes (OR) de SA étaient de 0,728 (P = 4,3608 × 10-8), 1,063 (P = 0,0321), 0,926 (P = 9,4205 × 10-4), 1,141 (P = 7,9882 ×10-3), 5,154 (P = 0,0420), 1,220 (P = 0,0350), 1,228 (P = 0,0117), 0,795 (P = 0,0056), 1,126 (P = 0,0318), pour une augmentation d'un écart type (ET) de AFS, AAM, AFB, initiation au tabagisme, tabagisme/fumeurs dans le ménage, pourcentage de graisse dans les bras (gauche), pourcentage de graisse dans les jambes (gauche), tour de taille et pourcentage de graisse corporelle, 0,925 (P = 0,4158) et 1,075 (P = 0,1479) pour une augmentation SD du tabagisme passé, pourcentage de graisse du tronc pour une augmentation SD de SA. En IRM multivariable (MVMR), seuls l'AFS (OR = 0,802 ; P = 0,0250), l'initiation au tabagisme (OR = 1,472, P = 0,0258), le tour de taille (OR = 0,813, P = 0,0220) et le pourcentage de graisse dans les jambes (à gauche) ( OR = 4,446, P = 0,043) a conservé un effet robuste.

Conclusion : Les comportements tabagiques, les traits de reproduction et les indicateurs anthropométriques liés à l'obésité sont des facteurs causals potentiels de l'AS. Pourcentage de graisse des jambes plus élevé ; initiation au tabagisme ; et le tour de taille inférieur et l'AFS peuvent augmenter le risque d'AS. Comprendre la relation causale pour l'AS peut fournir plus d'informations pour les stratégies d'intervention et de prévention de l'AS.
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Re: Effet des vitamines/oméga chez la femme enceinte sur le

Messagepar Nutrimuscle-Conseils » 1 Aoû 2023 11:55

Maternal dietary fiber intake during pregnancy and child development: the Japan Environment and Children's Study
Kunio Miyake Front. Nutr., 27 July 2023

Background: Animal studies have shown that maternal low-fiber diets during pregnancy may impair brain development and function in offspring, but this has not been validated by epidemiological studies. The aim of this study was to investigate the link between maternal dietary fiber intake during pregnancy and neurodevelopmental delay in offspring using a large birth cohort.

Methods: A total of 76,207 mother-infant pairs were analyzed using data from the Japan Environment and Children's Study, a nationwide prospective cohort study. Maternal dietary fiber intake was estimated using the food frequency questionnaire in mid-pregnancy. Maternal dietary fiber intake was adjusted for energy and classified into quintiles. Developmental delay was assessed in five domains using the Japanese version of the Ages and Stages Questionnaire, Third Edition at the age of 3 years. The logistic regression analysis was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) for the link between dietary fiber intake during pregnancy and developmental delay at the age of 3 years.

Results: The lowest intake group of total dietary fiber had a higher risk of delayed communication [adjusted OR (aOR), 1.51; 95% CI, 1.32–1.74], fine motor (aOR, 1.45; 95% CI, 1.32–1.61), problem-solving (aOR, 1.46; 95% CI, 1.32–1.61), and personal-social skills (aOR, 1.30; 95% CI, 1.12–1.50) than did the highest intake group. An analysis that excluded the effects of insufficient folic acid intake during pregnancy also showed a similar trend.

Conclusion: This study showed that maternal dietary fiber deficiency during pregnancy might influence an increased risk of neurodevelopmental delay in offspring.
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Messagepar Nutrimuscle-Diététique » 2 Aoû 2023 16:12

Traduction de l'étude :wink:

Apport maternel en fibres alimentaires pendant la grossesse et le développement de l'enfant : l'étude japonaise sur l'environnement et les enfants
Devant Kunio Miyake. Nutr., 27 juillet 2023

Contexte : Des études animales ont montré que les régimes maternels pauvres en fibres pendant la grossesse peuvent altérer le développement et le fonctionnement du cerveau chez la progéniture, mais cela n'a pas été validé par des études épidémiologiques. Le but de cette étude était d'étudier le lien entre l'apport maternel en fibres alimentaires pendant la grossesse et le retard de développement neurologique chez la progéniture à l'aide d'une grande cohorte de naissance.

Méthodes : Au total, 76 207 paires mère-enfant ont été analysées à l'aide des données de l'étude japonaise sur l'environnement et les enfants, une étude de cohorte prospective à l'échelle nationale. L'apport maternel en fibres alimentaires a été estimé à l'aide du questionnaire de fréquence alimentaire au milieu de la grossesse. L'apport maternel en fibres alimentaires a été ajusté en fonction de l'énergie et classé en quintiles. Le retard de développement a été évalué dans cinq domaines à l'aide de la version japonaise du questionnaire Ages and Stages, troisième édition à l'âge de 3 ans. L'analyse de régression logistique a été réalisée pour estimer l'odds ratio (OR) et l'intervalle de confiance (IC) à 95% pour le lien entre l'apport en fibres alimentaires pendant la grossesse et le retard de développement à l'âge de 3 ans.

Résultats : Le groupe ayant le plus faible apport en fibres alimentaires totales présentait un risque plus élevé de retard de communication [OR ajusté (aOR), 1,51 ; IC à 95 %, 1,32-1,74], la motricité fine (ORa, 1,45 ; IC à 95 %, 1,32-1,61), la résolution de problèmes (ORa, 1,46 ; IC à 95 %, 1,32-1,61) et les compétences personnelles et sociales (ORa, 1,30 ; IC à 95 %, 1,12 à 1,50) que le groupe d'apport le plus élevé. Une analyse qui excluait les effets d'un apport insuffisant en acide folique pendant la grossesse a également montré une tendance similaire.

Conclusion : Cette étude a montré qu'une carence maternelle en fibres alimentaires pendant la grossesse pourrait influencer un risque accru de retard de développement neurologique chez la progéniture.
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Messagepar Nutrimuscle-Conseils » 8 Aoû 2023 07:09

Folic Acid Supplementation to Prevent Neural Tube Defects
Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Meera Viswanathan JAMA. 2023;330(5):460-466.

Abstract
Importance Neural tube defects are among the most common birth defects in the US.

Objective To review new evidence on the benefits and harms of folic acid supplementation for the prevention of neural tube defects to inform the US Preventive Services Task Force.

Evidence Review Sources included PubMed, Cochrane Library, Embase, and trial registries from July 1, 2015, through July 2, 2021; references; and experts, with surveillance through February 10, 2023. Two investigators independently reviewed English-language randomized studies and nonrandomized cohort studies in very highly developed countries that focused on the use of folic acid supplementation for the prevention of neural tube defect–affected pregnancies; methodological quality was dually and independently assessed.

Findings Twelve observational studies (reported in 13 publications) were eligible for this limited update (N = 1 244 072). Of these, 3 studies (n = 990 372) reported on the effect of folic acid supplementation on neural tube defects. For harms, 9 studies were eligible: 1 randomized clinical trial (n = 431) reported on variations in twin delivery, 7 observational studies (n = 761 125) reported on the incidence of autism spectrum disorder, and 1 observational study (n = 429 004) reported on maternal cancer. Two cohort studies and 1 case-control study newly identified in this update reported on the association between folic acid supplementation and neural tube defects (n = 990 372). One cohort study reported a statistically significant reduced risk of neural tube defects associated with folic acid supplementation taken before pregnancy (adjusted relative risk [aRR], 0.54 [95% CI, 0.31-0.91]), during pregnancy (aRR, 0.62 [95% CI, 0.39-0.97]), and before and during pregnancy (aRR, 0.49 [95% CI, 0.29-0.83]), but this association occurred for only the later of 2 periods studied (2006-2013 and not 1999-2005). No other statistically significant benefits were reported overall. No study reported statistically significant harms (multiple gestation, autism, and maternal cancer) associated with pregnancy-related folic acid exposure.

Conclusions and Relevance New evidence from observational studies provided additional evidence of the benefit of folic acid supplementation for preventing neural tube defects and no evidence of harms related to multiple gestation, autism, or maternal cancer. The new evidence was consistent with previously reviewed evidence on benefits and harms.

Introduction
Neural tube defects are major congenital malformations often caused by low folate concentrations in the body at the time of conception. These defects frequently result in significant disability or death for affected fetuses and children. Strategies that enhance folic acid uptake before pregnancy offer the best chance of prevention.

In 2017, the US Preventive Services Task Force (USPSTF) concluded that folic acid supplementation in the periconceptional period has substantial benefits in reducing the risk of neural tube defects in the developing fetus1 and reaffirmed its 2009 recommendation that all persons who are planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg (400-800 μg) of folic acid (A recommendation). The 2017 USPSTF recommendation was based on previously reviewed evidence from a randomized clinical trial and observational studies reporting reduced neural tube defects with supplementation and no consistent evidence of harms such as multiple gestation, maternal adverse effects, or child respiratory illness.

This limited evidence update aimed to identify studies published since the previous (2017) evidence review2 conducted for the USPSTF to inform a reaffirmation of the current recommendation.

Methods
An analytic framework and 2 key questions guided the limited evidence update (Figure). A literature search of PubMed/MEDLINE, the Cochrane Library, Embase, and trial registries was conducted from July 1, 2015, through July 2, 2021. Additional sources included reference lists of retrieved articles, outside experts, and public commenters, with ongoing surveillance of the literature through February 10, 2023. Two investigators independently evaluated the eligibility of all abstracts and articles and rated study quality using predefined criteria.4 Detailed methods and results are available in the full evidence report.4

English-language randomized and nonrandomized studies that focused on the use of folic acid supplementation (by itself or in multivitamins) for the prevention of neural tube defect–affected pregnancies in persons capable of getting pregnant were eligible. Studies conducted in very highly developed countries and that investigated potential harms of folic acid supplementation, such as maternal cancer and autism spectrum disorder, were also eligible. Ineligible studies included poor-quality studies and those focusing solely on persons taking antiseizure medications or with a history of neural tube defects in previous pregnancies.

Results
Twelve observational studies (reported in 13 publications5-17) (Table) were eligible for this limited update (N = 1 244 072 [from nonoverlapping cohorts]). Of these, 3 studies (n = 990 372) assessed the effect of folic acid supplementation on neural tube defects.5-8 No studies examined differences by race or ethnicity. For harms, 9 studies were eligible; 1 randomized clinical trial (n = 431) assessed variations in twin delivery,9 7 observational studies (n = 761 125) examined the incidence of autism spectrum disorders,10-16 and 1 observational study (n = 429 004) reported on maternal cancer.17 The Table also reports details on studies from the 2017 evidence review.18-47

Benefits of Folic Acid Supplementation
Regarding the benefits of folic acid supplementation, 2 cohort studies and 1 case-control study in this update examined the association between folic acid supplementation and neural tube defects (n = 990 372).5-8 Food fortification and supplementation practices varied by setting. Of these studies, 1 cohort study set in Norway (no mandatory fortification) reported on neural tube defects among live births and stillborn infants from 1999 to 2013 overall and also stratified results into 2 separate periods: 1999 to 2005 and 2006 to 2013.6 The authors performed this stratified analysis because they found that the overall adjusted relative risk (aRR) was affected by year of birth. Several external events of importance were cited to explain differences by period: the introduction of folic acid recommendations in 1999, inclusion of 0.2 mg of folic acid in multivitamin supplements from 2004 onward (before 2004, most multivitamins did not include folic acid), and increased adherence to folic acid recommendations in the second half of the period analyzed (2006-2013).6 The authors reported no statistically significant benefits in the first of the 2 periods (1999-2005), regardless of timing of supplementation (before pregnancy, during pregnancy, or before and during pregnancy). In contrast, in the second period (2006-2013), the authors reported a statistically significant reduced risk of neural tube defects associated with folic acid supplementation taken before pregnancy (aRR, 0.54 [95% CI, 0.31-0.91]), during pregnancy (aRR, 0.62 [95% CI, 0.39-0.97]), and before and during pregnancy (aRR, 0.49 [95% CI, 0.29-0.83]).6

The second cohort study, set in Japan (no mandatory food fortification), reported no statistically significant differences associated with adequate (preconception) folic acid supplementation (adjusted odds ratio [aOR], 0.62 [95% CI, 0.23-1.71]) when compared with inadequate use (use after pregnancy recognition or no use).5 The third study, a case-control study set in the US and Canada in the period following food fortification, reported on participants with pregestational diabetes and prepregnancy obesity.8 The study reported that cases occurred more often among persons with unplanned pregnancies.8 Authors reported a statistically significant reduction in neural tube defects in women with prepregnancy obesity taking 0.4 mg to 1 mg of folic acid, when compared with women taking no supplementation and adjusting for maternal age (aOR, 0.54 [95% CI, 0.29-0.95]).8 Results adjusting for planned pregnancy rather than maternal age were similar but not statistically significant (aOR, 0.57 [95% CI, 0.30-1.02]).8 Across all 3 studies, no other statistically significant benefits were reported overall or by dose (1 study8) or timing (1 study6,7).

Harms of Folic Acid Supplementation
No study of harms (multiple gestation, autism, and maternal cancer) reported significant associations with pregnancy-related folic acid exposure.9-17

Discussion
This evidence review identified 3 new observational studies reporting on the association between folic acid supplementation before or during pregnancy and neural tube defects in offspring. Mandatory food fortification and supplementation practices varied by geography and period of investigation and contributed to heterogeneity across studies. Nevertheless, these new studies provided additional evidence of the benefit of folic acid supplementation for preventing neural tube defects. Nine new observational studies found no evidence of harms related to multiple gestation, autism, or maternal cancer. This new evidence is consistent with previously reviewed evidence on the benefits and harms of folic acid supplementation to prevent neural tube defects.
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Messagepar Nutrimuscle-Conseils » 8 Aoû 2023 07:11

Folic Acid Supplementation to Prevent Neural Tube Defects
US Preventive Services Task Force Reaffirmation Recommendation Statement

JAMA. 2023;330(5):454-459. doi:10.1001/jama.2023.12876

Abstract
Importance Neural tube defects are among the most common congenital malformations in the US, with an estimated 3000 pregnancies affected each year. Many of these neural tube defects are caused by low folate levels in the body.

Objective The US Preventive Services Task Force (USPSTF) commissioned a reaffirmation evidence update on the benefits and harms of folic acid supplementation.

Population Persons who are planning to or could become pregnant.

Evidence Assessment The USPSTF concludes that, for persons who are planning to or could become pregnant, there is high certainty that folic acid supplementation has a substantial net benefit to prevent neural tube defects in their offspring.

Recommendation The USPSTF recommends that all persons planning to or who could become pregnant take a daily supplement containing 0.4 to 0.8 mg (400 to 800 μg) of folic acid. (A recommendation)

Pathway to Benefit
To achieve benefit, persons planning to or who could become pregnant should start daily folic acid supplementation at least 1 month prior to anticipated conception and continue through the first 2 to 3 months of pregnancy.

Preamble
The US Preventive Services Task Force (USPSTF) makes recommendations about the effectiveness of specific preventive care services for patients without obvious related signs or symptoms to improve the health of people nationwide.

It bases its recommendations on the evidence of both the benefits and harms of the service and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment.

The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decision-making to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.

The USPSTF is committed to mitigating the health inequities that prevent many people from fully benefiting from preventive services. Systemic or structural racism results in policies and practices, including health care delivery, that can lead to inequities in health. The USPSTF recognizes that race, ethnicity, and gender are all social rather than biological constructs. However, they are also often important predictors of health risk. The USPSTF is committed to helping reverse the negative impacts of systemic and structural racism, gender-based discrimination, bias, and other sources of health inequities, and their effects on health, throughout its work.

Importance
Neural tube defects are among the most common congenital malformations in the US, with an estimated 3000 pregnancies affected each year.1 Many of these neural tube defects are caused by low folate levels in the body of the pregnant person. The Centers for Disease Control and Prevention estimated that spina bifida occurs in 3.9 of 10 000 live births in the US, anencephaly in 2.5 of 10 000 live births, and encephalocele in 1 of 10 000 live births.2 Neural tube defects can result in death and a range of disabilities affecting children. Children with encephaloceles have an increased mortality rate, with many survivors having neurologic and developmental deficits.3-5 Common disabilities from spina bifida include lower limb weakness and paralysis, sensory loss, bowel and bladder dysfunction, orthopedic abnormalities (eg, clubfoot, contractures, hip dislocation, scoliosis, or kyphosis), and ventriculomegaly (which may require placement of ventricular-peritoneal shunts).6-8 Anencephaly is life-limiting in early infancy.9

Folate refers to vitamin B9, a water-soluble B vitamin that occurs in many chemical forms, including naturally in foods such as leafy greens, fruits, nuts, beans, peas, seafood, eggs, dairy products, meat, and poultry.10 Folic acid is the term applied to the synthetic form of folate that is found in supplements and added to fortified foods. Folic acid supplementation for persons in the periconceptional period has been found to reduce the risk of neural tube defects in offspring.11,12 Despite folic acid fortification of food and supplementation guidelines, folic acid deficiency remains a concern in the US. Low levels of maternal folate may be due to inadequate dietary intake, poor intestinal absorption, medication use that interferes with folic acid function, and impaired folate metabolism.10 Survey data from 1998 to 2016 found that approximately 20% to 40% of women who were recently pregnant or trying to get pregnant reported taking periconceptional folic acid supplements, and those with an unintended pregnancy were 4 to 5 times less likely to have taken periconceptional folic acid supplements.10

USPSTF Assessment of Magnitude of Net Benefit
In 2017, the USPSTF reviewed the evidence for folic acid supplementation and issued an A recommendation.12 The USPSTF has decided to use a reaffirmation deliberation process to update this recommendation. The USPSTF uses the reaffirmation process for well-established, evidence-based current standards of practice in primary care for which only a very high level of evidence would justify a change in the grade of the recommendation. In its deliberation of the evidence, the USPSTF considers whether the new evidence is of sufficient strength and quality to change its previous conclusions about the evidence.

Using a reaffirmation process, the USPSTF concludes that, for persons who are planning to or could become pregnant, there is high certainty that folic acid supplementation has a substantial net benefit.

See the Table for more information on the USPSTF recommendation rationale and assessment and the eFigure in the Supplement for information on the recommendation grade. See the Figure for a summary of the recommendation for clinicians. For more details on the methods the USPSTF uses to determine net benefit, see the USPSTF Procedure Manual.13

Practice Considerations
Patient Population Under Consideration
This recommendation applies to persons who are planning to or could become pregnant. It does not apply to persons who have had a previous pregnancy affected by neural tube defects or who are at very high risk because of other factors (eg, use of certain antiseizure medications or family history). It does not apply to persons taking certain medications known to block the function of folic acid (eg, methotrexate, carbamazepine, and valproic acid).

Definitions
Neural tube defects are caused by a failure of closure of the embryonic neural tube, which results in birth defects of the brain, spinal cord, and overlying tissues. The most common forms of neural tube defects are anencephaly, encephalocele, and spina bifida.14 Anencephaly occurs when the cranial portion of the neural tube fails to close. Affected infants are born without portions of the brain and skull. Anencephaly is life-limiting in early infancy. Encephalocele occurs when cranial defects allow portions of the brain and meninges to protrude. Spina bifida is a group of conditions that vary in severity and include myelomeningocele (protrusion of the spinal cord and meninges through a spinal defect), meningocele (protrusion of meninges through a spinal defect), and spina bifida occulta (spinal defect without any protrusion).10

Assessment of Risk
All pregnancies are at risk for neural tube defects, and persons who are planning to or could become pregnant should take folic acid supplements. Certain risk factors convey a higher risk, and individuals with these risk factors should talk to their health care professional. These factors include personal, partner, or family history of neural tube defects, malabsorption caused by bariatric procedures, the use of certain antiseizure medicines, and genetic mutations in folate-related enzymes.15-19 Pregestational diabetes and obesity have been associated with an increased risk of neural tube defects.20,21 Ethnic groups such as First Nation persons in Canada and Hispanic persons in California are thought to be at higher risk of neural tube defects.22,23 It is unclear, however, whether this is related to a higher risk of genetic variations among these groups or due to differential intake of folic acid–fortified foods.10

Timing
The neural plate completes its formation and closure early in pregnancy (usually 26 to 28 days after fertilization).17 This means the critical period for folic acid supplementation starts at least 1 month before conception and continues through the first 2 to 3 months of pregnancy. Nearly half of all pregnancies in the US are unplanned; to gain the full benefits of supplementation, clinicians should advise all persons who plan to or who could become pregnant to take daily folic acid.24

Dosage
Good evidence from studies in settings without fortification of food suggests that an over-the-counter multivitamin with between 0.4 mg (400 μg) (the generally available dose) and 0.8 mg (800 μg) of folic acid daily reduces the risk for neural tube defects.10,12 Clinical practice guidelines from professional medical and public health organizations recommend a minimum folic acid supplemental daily intake of 400 μg for all persons who are planning a pregnancy or could become pregnant.25-28

Since 1998, specific enriched cereal grain products in the US have been fortified with folic acid. In 2016, the US Food and Drug Administration began allowing corn masa flour to be voluntarily fortified with folic acid.10 Evidence shows that persons who may become pregnant are not consuming fortified foods at a quantity to provide optimal benefit for prevention of neural tube defects.12,29 Therefore, all persons planning to or who could become pregnant should take a daily supplement of at least 400 ug.

Additional Tools and Resources
The Community Preventive Services Task Force recommends community-wide education campaigns to promote the use of folic acid supplements among persons of childbearing age (https://www.thecommunityguide.org/findi ... ments.html).

Reaffirmation of Previous USPSTF Recommendation
This recommendation is a reaffirmation of the USPSTF 2017 recommendation statement. In 2017, the USPSTF reviewed the evidence for folic acid supplementation to prevent neural tube defects and found convincing evidence that the benefits of supplementation substantially outweighed the harms (A recommendation).12 In the current update, the USPSTF found no new substantial evidence that could change its recommendation and, therefore, reaffirms its recommendation that all persons planning to or who could become pregnant take a daily supplement of folic acid.

Supporting Evidence
Scope of Review
To reaffirm its recommendation, the USPSTF commissioned a reaffirmation evidence update.10,30 The aim of evidence updates that support the reaffirmation process is to identify new and substantial evidence sufficient to change the prior recommendation.13 The reaffirmation update focuses on targeted key questions on the benefits and harms of folic acid supplementation.

Benefits of Folic Acid Supplementation
In 2017, the USPSTF reviewed the evidence on the benefits of folic acid supplementation to prevent neural tube defects and found convincing evidence that the benefits of supplementation were significant. Three fair-quality observational studies (reported in 4 publications) published since the last USPSTF recommendation reported on the association between folic acid supplementation and neural tube defects (n = 990 372).10,30 Two cohort studies were in populations without food fortification (Norway and Japan) and the third was a case-control study set in the US and Canada prior to and after the introduction of food fortification.10,30 The Norwegian cohort study (n = 896 674 live births and stillborn infants) reported results by time periods (1999-2005, 2006-2013, and overall, 1999-2013).31,32 In Norway, folic acid supplementation was first recommended in 1999 and folic acid was not included in most multivitamins until 2004. The authors hypothesized that the study periods corresponded to lesser (1999-2005) and greater (2006-2013) adherence to recommendations regarding folic acid supplementation. The study reported a statistically significant reduction in neural tube defects in women taking folic acid supplementation in the period corresponding to greater adherence (2006 to 2013) but not in other periods. The Japanese cohort (n = 92 269) compared adequate users of folic acid supplements (started before conception) with inadequate users (started after pregnancy recognition or nonuse of folic acid supplements). Neural tube defect outcomes included spina bifida, anencephaly, and encephalocele. The study reported no statistically significant differences associated with folic acid supplementation.33 Both cohort studies drew from general populations. The case-control study set in the US and Canada in the period following food fortification focused on high-risk participants. A subgroup of participants (123 cases and 1306 controls) with pregestational diabetes and prepregnancy obesity was included in the review. This study reported no statistically significant associations between daily or less than daily folic acid supplementation, compared with no supplementation, and neural tube defects.34

The USPSTF also reviewed data on whether the benefits of folic acid supplementation differ by timing. In the previously mentioned Norwegian study, there was no effect of folic acid supplementation regardless of the timing of folic acid supplementation in the period corresponding to lesser adherence (1999-2005) and in the overall period (1999-2013). In the second period (2006-2013), the results demonstrated a benefit of folic acid supplementation regardless of timing (before pregnancy only: adjusted relative risk [aRR], 0.54 [95% CI, 0.31-0.91]; before and during pregnancy: aRR, 0.49 [95% CI, 0.29-0.83]; and during pregnancy only: aRR, 0.62 [95% CI, 0.39-0.97]).10,30

Harms of Folic Acid Supplementation
In 2017, the USPSTF reviewed the evidence on the harms of folic acid supplementation to prevent neural tube defects and found adequate evidence that folic acid supplementation at usual doses is not associated with serious harms. Six fair-quality cohort studies and 1 fair-quality case-control study published since the 2017 USPSTF recommendation examined the potential association between folic acid supplementation and autism spectrum disorder (ASD) (n = 761 125).10,30 No study reported statistically significant associations between supplementation and increased risk of ASD. Two studies reported statistically significant reductions of autism associated with folic acid supplementation. Other studies in similar geographic settings or populations that used different measures of exposure or comparators reported no association between folic acid supplementation and autism. Three studies reported on associations between folic acid supplementation and ASD by dose and found no differences. Two studies reported on associations between folic acid supplementation and ASD by timing. Neither reported harms; however, 1 study reported a statistically significant reduction of ASD associated with folic acid supplementation initiation in weeks 5 to 8 of the pregnancy.10,30

One high-quality trial reported on the differences in twin deliveries based on the dose of folic acid. It found no differences between an exposure of 4 mg vs 0.4 mg of folic acid daily. No studies reported on the overall risk, timing, or duration of twin gestations and folic acid supplementation.10,30 One cohort study (n = 429 004) found no association between folic acid supplementation and maternal cancer.10,30

How Does Evidence Fit With Biological Understanding?
Adequate maternal folate levels are important in preventing neural tube defects; however, the mechanism by which folate reduces this risk is not well understood. Folate is necessary for nucleotide synthesis and DNA and RNA function.10 Inadequate folate levels impair nucleotide synthesis and DNA and RNA replication, and may lead to incomplete neural folds and subsequent neural tube defects.

Response to Public Comment
A draft version of this recommendation statement was posted for public comment on the USPSTF website from February 21, 2023, to March 20, 2023. Most comments agreed with the conclusions of the USPSTF. Commenters requested additional information on the dosage of folic acid. The USPSTF wishes to clarify that the generally available dosage for folic acid supplementation is between 0.4 and 0.8 mg daily. The most common dosages from the included studies were in this range. Women at higher risk of neural tube defects may require dosages above this range and should speak with their clinician about this. Based on comments, the USPSTF also included information on naturally occurring sources of folate.

Research Needs and Gaps
Studies are needed that provide more information on the following.

More research is needed to better understand how genetic variants such as MTHFR slow folate metabolism and how these variants affect strategies for folic acid supplementation.

More research is needed on the effectiveness of folic acid supplementation in reducing neural tube defects among those disproportionately affected by the condition, including Hispanic persons.

More research is needed on factors that contribute to variations in adherence to supplementation.

Recommendations of Others
The American College of Obstetricians and Gynecologists, American Academy of Family Physicians, and American Academy of Pediatrics all recommend folic acid supplementation of 400 μg (0.4 mg) per day for persons of reproductive age who are planning to become pregnant and are at average risk of neural tube defects (ie, without a prior pregnancy with a neural tube defect).25-27
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