Effect of women's nutrition before and during early pregnancy on maternal and infant outcomes: a systematic review

Current understanding of biologic processes indicates that women's nutritional status before and during early pregnancy may play an important role in determining early developmental processes and ensuring successful pregnancy outcomes. We conducted a systematic review of the evidence for the impact of maternal nutrition before and during early pregnancy (<12 weeks gestation) on maternal, neonatal and child health outcomes and included 45 articles (nine intervention trials and 32 observational studies) that were identified through PubMed and EMBASE database searches and examining review articles. Intervention trials and observational studies show that periconceptional (<12 weeks gestation) folic acid supplementation significantly reduced the risk of neural tube defects. Observational studies suggest that preconceptional and periconceptional intake of vitamin and mineral supplements is associated with a reduced risk of delivering offspring who are low birthweight and/or small-for-gestational age (SGA) and preterm deliveries (PTD). Some studies report that indicators of maternal prepregnancy size, low stature, underweight and overweight are associated with increased risks of PTD and SGA. The available data indicate the importance of women's nutrition prior to and during the first trimester of pregnancy, but there is a need for well-designed prospective studies and controlled trials in developing country settings that examine relationships with low birthweight, SGA, PTD, stillbirth and maternal and neonatal mortality. The knowledge gaps that need to be addressed include the evaluation of periconceptional interventions such as food supplements, multivitamin-mineral supplements and/or specific micronutrients (iron, zinc, iodine, vitamin B-6 and B-12) as well as the relationship between measures of prepregnancy body size and composition and maternal, neonatal and child health outcomes.     

The Effectiveness of Smoking Cessation,Alcohol Reduction,Diet and Physical Activity Interventions in Improving Maternal and Infant Health Outcomes: A Systematic Review of Meta-Analyses

Diet, physical activity, smoking and alcohol behaviour-change interventions delivered in pregnancy aim to prevent adverse pregnancy outcomes. This review reports a synthesis of evidence from meta-analyses on the effectiveness of interventions at reducing risk of adverse health outcomes. Sixty-five systematic reviews (63 diet and physical activity; 2 smoking) reporting 602 meta-analyses, published since 2011, were identified; no data were identified for alcohol interventions. A wide range of outcomes were reported, including gestational weight gain, hypertensive disorders, gestational diabetes (GDM) and fetal growth. There was consistent evidence from diet and physical activity interventions for a significantly reduced mean gestational weight gain (ranging from −0.21 kg (95% confidence interval −0.34, −0.08) to −5.77 kg (95% CI −9.34, −2.21). There was evidence from larger diet and physical activity meta-analyses for a significant reduction in postnatal weight retention, caesarean delivery, preeclampsia, hypertension, GDM and preterm delivery, and for smoking interventions to significantly increase birth weight. There was no statistically significant evidence of interventions having an effect on low or high birthweight, neonatal intensive care unit admission, Apgar score or mortality outcomes. Priority areas for future research to capitalise on pregnancy as an opportunity to improve the lifelong wellbeing of women and their children are highlighted.     

Is Supplementation with Micronutrients Still Necessary during Pregnancy? A Review

Introduction: Proper nutrition during pregnancy is important to prevent nutritional imbalances that interfere with pregnancy. Micronutrients play critical roles in embryogenesis, fetal growth, and maternal health, as energy, protein, vitamin, and mineral needs can increase during pregnancy. Increased needs can be met by increasing the intake of dietary micronutrients. Severe micronutrient deficiency or excess during pregnancy can have negative effects on fetal growth (intrauterine growth retardation, low birth weight, or congenital malformations) and pregnancy development (pre-eclampsia or gestational diabetes). We investigate whether it is necessary to continue micronutrient supplementation during pregnancy to improve women’s health in this stage and whether this supplementation could prevent and control pathologies associated with pregnancy. Aim: The present review aims to summarize evidence on the effects of nutritional deficiencies on maternal and newborn morbidity. Methods: This aim is addressed by critically reviewing results from published studies on supplementation with different nutrients during pregnancy. For this, major scientific databases, scientific texts, and official webpages have been consulted. PubMed searches using the terms “pregnancy” OR “maternal-fetal health” AND “vitamins” OR “minerals” OR “supplementation” AND “requirement” OR “deficiency nutrients” were performed. Results: There are accepted interventions during pregnancy, such as folic acid supplementation to prevent congenital neural tube defects, potassium iodide supplementation to correct neurodevelopment, and oral iron supplementation during the second half of pregnancy to reduce the risk of maternal anemia and iron deficiency. A number of micronutrients have also been associated with pre-eclampsia, gestational diabetes mellitus, and nausea and vomiting in pregnancy. In general, experimental studies are necessary to demonstrate the benefits of supplementation with different micronutrients and to adjust the recommended daily doses and the recommended periconceptional nutrition for mothers. Conclusions: Presently, there is evidence of the benefits of micronutrient supplementation in perinatal results, but indiscriminate use is discouraged due to the fact that the side effects of excessive doses are not known. Evidence supports the idea that micronutrient deficiencies negatively affect maternal health and the outcome of pregnancy. No single micronutrient is responsible for the adverse effects; thus, supplementing or correcting one deficiency will not be very effective while other deficiencies exist.     

Impact of Maternal Nutritional Supplementation during Pregnancy and Lactation on the Infant Gut or Breastmilk Microbiota: A Systematic Review

Recent evidence indicates that maternal dietary intake, including dietary supplements, during pregnancy and lactation may alter the infant gut or breastmilk microbiota, with implications for health outcomes in both the mother and infant. To review the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota a systematic literature search was conducted. A total of 967 studies published until February 2020 were found, 31 were eligible and 29 randomized control trials were included in the qualitative synthesis. There were 23 studies that investigated the effects of probiotic supplementation, with the remaining studies investigating vitamin D, prebiotics or lipid-based nutrient supplements (LNS). The effects of maternal nutritional supplementation on the infant gut microbiota or breastmilk microbiota were examined in 21 and 12 studies, respectively. Maternal probiotic supplementation during pregnancy and lactation generally resulted in the probiotic colonization of the infant gut microbiota, and although most studies also reported alterations in the infant gut bacterial loads, there was limited evidence of effects on bacterial diversity. The data available show that maternal probiotic supplementation during pregnancy or lactation results in probiotic colonization of the breastmilk microbiota. There were no observed effects between probiotic supplementation and breastmilk bacterial counts of healthy women, however, administration of Lactobacillus probiotic to nursing women affected by mastitis was associated with significant reductions in breastmilk Staphylococcal loads. Maternal LNS supplementation during pregnancy and lactation increased bacterial diversity in the infant gut, whilst vitamin D and prebiotic supplementation did not alter either infant gut bacterial diversity or counts. Heterogeneity in study design precludes any firm conclusions on the effects of maternal nutritional supplementation during pregnancy and lactation on the infant gut or breastmilk microbiota, warranting further research.     

Interventions with vitamins B6, B12 and C in pregnancy

The water-soluble vitamins B6, B12 and C play important roles in maternal health as well as fetal development and physiology during gestation. This systematic review evaluates the risks and benefits of interventions with vitamins B6, B12 and C during pregnancy on maternal, neonatal and child health and nutrition outcomes. Relevant publications were identified by searching PubMed, Popline and Web of Science databases. Meta-analyses were conducted for outcomes where results from at least three controlled trials were available. Potential benefits of vitamin B6 supplementation were reduction in nausea and vomiting, improvement in dental health, and treatment of some cases of anaemia. In meta-analysis based on three small studies, vitamin B6 supplementation had a significant positive effect on birthweight (d = 217 g [95% confidence interval (CI) 130, 304]). Interventions with vitamin C alone or combined with vitamin E did not systematically reduce the incidence of pre-eclampsia, premature rupture of membranes, or other adverse pregnancy outcomes. In meta-analyses, vitamins C and E increased the risk of pregnancy-related hypertension (relative risk 1.10 [95% CI 1.02, 1.19]). Effects of vitamin B6 or C intervention on other neonatal outcomes, including preterm birth, low birthweight, and perinatal morbidity and mortality, were not significant. Data on child health outcomes were lacking. Despite the prevalence of vitamin B12 deficiency amongst populations with limited intake of animal source foods, no intervention trials have evaluated vitamin B12 supplementation before or during pregnancy. In conclusion, existing evidence does not justify vitamin C supplementation during pregnancy. Additional studies are needed to confirm positive effects of vitamin B6 supplementation on infant birthweight and other outcomes. While vitamin B12 supplementation may reduce the incidence of neural tube defects in the offspring based on theoretical considerations, research is needed to support this hypothesis.     

Physical and mental health outcomes of prenatal maternal stress in human and animal studies: a review of recent evidence

Prenatal maternal stress (PNMS) has been linked with adverse health outcomes in the offspring through experimental studies using animal models and epidemiological studies of human populations. The purpose of this review article is to establish a parallel between animal and human studies, while focusing on methodological issues and gaps in knowledge. The review examines the quality of recent evidence for prevailing PNMS theoretical models, namely the biopsychosocial model for adverse pregnancy outcomes and the fetal programming model for chronic diseases. The investigators used PubMed (2000–06) to identify recently published original articles in the English language literature. A total of 103 (60 human and 43 animal) studies were examined.
Most human studies originated from developed countries, thus limiting generalisability to developing nations. Most animal studies were conducted on non-primates, rendering extrapolation of findings to pregnant women less straightforward. PNMS definition and measurement were heterogeneous across studies examining similar research questions, thus precluding the conduct of meta-analyses. In human studies, physical health outcomes were often restricted to birth complications while mental health outcomes included postnatal developmental disorders and psychiatric conditions in children, adolescents and adults. Diverse health outcomes were considered in animal studies, some being useful models for depression, schizophrenia or attention deficit hyperactivity disorder in human populations. The overall evidence is consistent with independent effects of PNMS on perinatal and postnatal outcomes. Intervention studies and large population-based cohort studies combining repeated multi-dimensional and standardised PNMS measurements with biomarkers of stress are needed to further understand PNMS aetiology and pathophysiology in human populations.     

Biological mechanisms for nutritional regulation of maternal health and fetal development

This review paper highlights mechanisms for nutritional regulation of maternal health and fetal development. Malnutrition (nutrient deficiencies or obesity) in pregnant women adversely affects their health by causing or exacerbating a plethora of problems, such as anaemia, maternal haemorrhage, insulin resistance, and hypertensive disorders (e.g. pre-eclampsia/eclampsia). Maternal malnutrition during gestation also impairs embryonic and fetal growth and development, resulting in deleterious outcomes, including intrauterine growth restriction (IUGR), low birthweight, preterm birth, and birth defects (e.g. neural tube defects and iodine deficiency disorders). IUGR and preterm birth contribute to high rates of neonatal morbidity and mortality. Major common mechanisms responsible for malnutrition-induced IUGR and preterm birth include: (i) abnormal growth and development of the placenta; (ii) impaired placental transfer of nutrients from mother to fetus; (iii) endocrine disorders; and (iv) disturbances in normal metabolic processes. Activation of a series of physiological responses leading to premature and sustained contraction of the uterine myometrium also results in preterm birth. Recent epidemiologic studies have suggested a link between IUGR and chronic metabolic disease in children and adults, and the effects of IUGR may be carried forward to subsequent generations through epigenetics. While advanced medical therapies, which are generally unavailable in low-income countries, are required to support preterm and IUGR infants, optimal nutrition during pregnancy may help ameliorate many of these problems. Future studies are necessary to develop effective nutritional interventions to enhance fetal growth and development and alleviate the burden of maternal morbidity and mortality in low- and middle-income countries.     

Pregnancy and lactation: physiological adjustments,nutritional requirements and the role of dietary supplements

Nutritional needs are increased during pregnancy and lactation for support of fetal and infant growth and development along with alterations in maternal tissues and metabolism. Total nutrient needs are not necessarily the sum of those accumulated in maternal tissues, products of pregnancy and lactation and those attributable to the maintenance of nonreproducing women. Maternal metabolism is adjusted through the elaboration of hormones that serve as mediators, redirecting nutrients to highly specialized maternal tissues specific to reproduction (i.e., placenta and mammary gland). It is most unlikely that the heightened nutrient needs for successful reproduction can always be met from the maternal diet. Requirements for energy-yielding macronutrients increase modestly compared with several micronutrients that are unevenly distributed among foods. Altered nutrient utilization and mobilization of reserves often offset enhanced needs but sometimes nutrient deficiencies are precipitated by reproduction. There are only limited data from well-controlled intervention studies with dietary supplements and with few exceptions (iron during pregnancy and folate during the periconceptional period), the evidence is not strong that nutrient supplements confer measurable benefit. More research is needed and in future studies attention must be given to subject characteristics that may influence ability to meet maternal and infant demands (genetic and environmental), nutrient-nutrient interactions, sensitivity and selectivity of measured outcomes and proper use of proxy measures. Consideration of these factors in future studies of pregnancy and lactation are necessary to provide an understanding of the links among maternal diet; nutritional supplementation; and fetal, infant and maternal health.     

A Review of the Impact of Dietary Intakes in Human Pregnancy on Infant Birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.     

Racial Disparity in Infant and Maternal Mortality: Confluence of Infection,and Microvascular Dysfunction

OBJECTIVES: Racial disparities in infant and maternal mortality have been attributed to the unique stresses faced by Black women in the United States, but the underlying pathophysiological pathways are poorly understood. This paper reviews the literature related to potential causes of racial disparities in infant and maternal mortality. METHODS: A review of the literature from 1966 to 2003 was conducted using a series of searches of Medline, obstetrical journals, and bibliographies. The review focused on potential contributing pathophysiological factors to infant and maternal mortality. RESULTS: Racial disparities in neonatal mortality largely result from excess rates of preterm birth, fetal growth restriction, and neonatal sepsis while racial disparities in maternal mortality reflect greater prevalence and/or severity of cardiovascular/preeclamptic complications, hemorrhage, and infection among African American women. A large body of epidemiological, placental, and pathophysiological evidence suggests that racial disparities in these disparate outcomes result from two distinct, but potentially converging, pathways: infection and vascular. Racial disparities in intrauterine infection and microvascular dysfunction during pregnancy may result from a constellation of environmental and intergenerational risk factors including psychosocial stress, douching, bottle-feeding, lead exposure, diet, intrauterine growth, and genes. CONCLUSIONS: Disparities in infant and maternal mortality appear to reflect a confluence of infections and microvascular dysfunction during pregnancy among African American women. Interventions that target these conditions offer promise for reducing racial disparities in these critical outcomes.     

Calcium Supplementation to Prevent Preeclampsia: Translating Guidelines into Practice in Low-Income Countries

The WHO issued a strong recommendation that pregnant women be provided calcium supplements to prevent preeclampsia. This is the first recommended nutritional intervention to prevent this condition, a leading cause of maternal mortality globally. As health systems seek to implement this new intervention, a number of issues require further clarification and guidance, including dosage regimen, supplement formulation, and alignment with other antenatal nutritional interventions. We summarize key evidence on the above points and offer our views on good practices. Most developing countries have low calcium intake, so where habitual calcium intake is unknown, calcium supplements are likely beneficial. In our view, policymakers and program planners should consider adopting doses between 1.0 and 1.5 g elemental calcium/d, depending on the local average and variation in dietary calcium intake, logistical feasibility, and acceptability in the target population. Prudent practice would entail daily administration as calcium carbonate administered in divided doses of not >500 mg elemental calcium per dose. For ease of prescribing and adherence, calcium [as with iron and folic acid (IFA)] should be administered routinely to pregnant women from the earliest contact in pregnancy until delivery. Calcium’s acute inhibitory effect on iron absorption translates to minimal effects in clinical studies. Therefore, to simplify the regimen and facilitate adherence, providers should not counsel that calcium and IFA pills must be taken separately. Although further research will shed more light on clinical and programmatic issues, policies can be implemented with ongoing revision as we continue to learn what works to improve maternal and newborn health.     

Maternal dietary diversity and odds of low birth weight: Empirical findings from India

India has the highest proportion of low birth weight (LBW) babies born in the developing world. Poor maternal nutrition during pregnancy is associated with adverse infant health outcomes. The main objective of this paper was to assess the socioeconomic factors associated with dietary diversity among pregnant women and to investigate the association between maternal dietary diversity and LBW among their babies. The data for these analyses were derived from a survey conducted in November and December, 2014 among 230 women who had newly delivered in hospitals in Uttar Pradesh, the largest Indian state that has the poorest maternal outcomes in the country. The results from multivariate binary logistic regression model indicated that low maternal education and economic status was significantly associated with poor dietary diversity among participants. Also, women with low maternal dietary diversity had a significantly higher proportion of LBW babies compared to those in the medium to high dietary diversity categories. From a policy perspective, these findings suggest that continuous tracking of pregnant women’s nutritional needs through existing monitoring systems, e.g., the Nutrition Resource Platform and Health Management Information System, and necessary interventions through Integrated Child Development Services may yield better results, thereby, addressing maternal under-nutrition and LBW.     

Human Milk Oligosaccharide Profiles and Associations with Maternal Nutritional Factors: A Scoping Review

Human milk oligosaccharides (HMOs) are complex unconjugated glycans associated with positive infant health outcomes. This study has examined current knowledge of the effect of maternal diet and nutritional status on the composition of HMOs in breast milk. Using the PRISMA-ScR guidelines, a comprehensive, systematic literature search was conducted using Scopus, Web of Science, Global Health (CABI), and MEDLINE. Titles and abstracts were screened independently by two reviewers against predefined inclusion and exclusion criteria. Fourteen studies met the inclusion criteria and reported on maternal dietary intake (n = 3), maternal body composition indices (n = 9), and dietary supplementation interventions (n = 2). In total, data from 1388 lactating mothers (4011 milk samples) were included. Design methodologies varied substantially across studies, particularly for milk sample collection, HMO analysis, dietary and body composition assessment. Overall, this review has identified potential associations between maternal dietary intake and nutritional status and the HMO composition of human milk, though an abundance and sufficiency of evidence is lacking. Standardised procedures for human milk sample collection and HMO analysis, along with robust and validated nutrition assessment techniques, should be employed to further investigate the impact of maternal nutritional factors on HMO composition.     

An Overview of Obesity,Cholesterol, and Systemic Inflammation in Preeclampsia

Preeclampsia (PE), an inflammatory state during pregnancy, is a significant cause of maternal and fetal morbidity and mortality. Adverse outcomes associated with PE include hypertension, proteinuria, uterine/placental abnormalities, fetal growth restriction, and pre-term birth. Women with obesity have an increased risk of developing PE likely due to impaired placental development from altered metabolic homeostasis. Inflammatory cytokines from maternal adipose tissue and circulating cholesterol have been linked to systemic inflammation, hypertension, and other adverse outcomes associated with PE. This review will summarize the current knowledge on the role of nutrients, obesity, and cholesterol signaling in PE with an emphasis on findings from preclinical models.     

Vitamin D-Related Risk Factors for Maternal Morbidity during Pregnancy: A Systematic Review

Vitamin D has well-defined classical functions related to metabolism and bone health but also has non-classical effects that may influence pregnancy. Maternal morbidity remains a significant health care concern worldwide, despite efforts to improve maternal health. Nutritional deficiencies of vitamin D during pregnancy are related to adverse pregnancy outcomes, but the evidence base is difficult to navigate. The primary purpose of this review is to map the evidence on the effects of deficiencies of vitamin D on pregnancy outcome and the dosage used in such studies. A systematic search was performed for studies on vitamin D status during pregnancy and maternal outcomes. A total of 50 studies came from PubMed, 15 studies came from Cochrane, and 150 studies came from Embase, for a total of 215 articles. After screening, 34 were identified as candidate studies for inclusion. Finally, 28 articles met the inclusion criteria, which originated from 15 countries. The studies included 14 original research studies and 13 review studies conducted between 2012 and 2021. This review was finally limited to the 14 original studies. This systematic review was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, and the quality and strength of the evidence was evaluated using the Navigation Guide Systematic Review Methodology (SING). We found evidence that supports the idea that supplementary vitamin D for pregnant women is important for reducing the risk of gestational diabetes, hypertension, preeclampsia, early labor, and other complications. The data retrieved from this review are consistent with the hypothesis that adequate vitamin D levels might contribute to a healthy pregnancy.     

Improving pregnancy outcome in obese women

The global pandemic of maternal obesity presents a major challenge for healthcare providers, and has significant short- and long-term implications for both maternal and fetal health. Currently, the evidence-base underpinning many of the interventions either currently in use or recommended to improve pregnancy outcome in obese women is limited. The nature and timing of these interventions vary widely, ranging from simple advice to more intensive dietary and exercise programmes, cognitive behavioural therapy and drug trials. In addition, a growing number of very severely obese women now enter pregnancy having had surgical interventions. Although surgical interventions such as gastric bypass or banding may be associated with improved pregnancy outcomes, these women have particular nutritional requirements, which need to be addressed to optimise pregnancy outcome. Until the outcomes of ongoing current trials are reported and provide a firm evidence base on which to base future intervention strategies and guide evidence based care for obese pregnant women, pregnancy outcome is best optimised by high-risk antenatal care delivered by healthcare providers who are experienced in supporting these high-risk women.     

Micronutrients in pregnancy

Vitamins and minerals, referred to collectively as micronutrients, have important influences on the health of pregnant women and the growing fetus. Iron deficiency results in anemia which may increase the risk of death from hemorrhage during delivery, but its effects on fetal development and birth outcomes is still unclear. Folic acid deficiency can lead to hematological consequences, pregnancy complications and congenital malformations, but again the association with other birth outcomes is equivocal. Zinc deficiency has been associated in some, but not all studies with complications of pregnancy and delivery, as well as with growth retardation, congenital abnormalities and retarded neurobehavioral and immunological development in the fetus. Iodine deficiency during pregnancy results in cretinism and possible fetal wastage and preterm delivery. Deficiency of other minerals such as magnesium, selenium, copper, and calcium have also been associated with complications of pregnancy, childbirth or fetal development. Deficiencies of vitamins other than folate may likewise be related to such complications; and vitamin A or beta-carotene supplements in pregnancy reduced maternal mortality by 50 % in a controlled trial in Nepal. Additional research is need on the prevalence of such deficiencies and their consequences and on cost-effective public health interventions for their control.     

高龄产妇妊娠期并发症及母婴结局分析

目的探讨高龄初产妇及经产妇妊娠期并发症及妊娠结局。方法回顾性分析2012年3月至2016年10月在山西医科大学第一医院住院分娩的10248例孕产妇病历资料,高龄产妇组1460例,适龄产妇组8788例,比较两组产妇的妊娠期并发症及母婴结局。同时按照初产妇、经产妇进行分层分析,比较高龄对初产妇及经产妇的不同影响。结果高龄组发生妊娠期糖尿病、妊娠期高血压疾病、前置胎盘、产后大出血、剖宫产、巨大儿、早产的发生风险是适龄产妇的1.485倍、1.320倍、1.409倍、1.642倍、1.670倍、1.299倍、1.440倍和1.233倍。按照初产妇和经产妇进行分层分析,初产妇高龄组发生妊娠期糖尿病、前置胎盘、胎盘早剥、产后大出血、剖宫产和早产的发生风险是适龄产妇的2.754倍、1.436倍、2.309倍、2.728倍、1.993倍和1.233倍。经产妇高龄组发生妊娠期糖尿病、妊娠期高血压疾病、前置胎盘、产后大出血、剖宫产、巨大儿和早产的发生风险是适龄产妇的1.356倍、1.326倍、1.452倍、1.505倍、1.571倍、1.351倍和1.266倍。结论高龄产妇妊娠期并发症及母婴不良结局的发生风险高于适龄妊娠产妇,高龄初产妇较适龄初产妇更容易发生胎盘早剥,高龄经产妇早产的发生风险较高。     

Folic acid supplements modify the adverse effects of maternal smoking on fetal growth and neonatal complications

Maternal smoking during pregnancy leads to increased risks of neonatal complications. The use of folic acid supplements might reduce the adverse effects of smoking. We examined whether folic acid supplement use modifies the associations of maternal smoking with first trimester plasma homocysteine concentrations, fetal growth characteristics, and risks of neonatal complications. The associations were studied in 6294 mothers participating in a prospective population-based cohort study in The Netherlands. Main outcomes measurements were first trimester plasma homocysteine concentrations, fetal growth characteristics, and neonatal complications, including preterm birth, low birth weight, and small-size-for-gestational-age. Continued maternal smoking was associated with higher first trimester plasma homocysteine concentrations [difference 0.52 μmol/L (95% range = 0.20, 2.14)], lower third trimester fetal weight (difference -44 g (95% CI = -57, -31)], and birth weight [difference -148 g (95% CI = -179, -118)]. There were significant interactions between maternal smoking and folic acid supplements on all outcome measures (all P-interaction < 0.040). Among mothers who continued smoking during pregnancy, those who did not use folic acid supplements had the highest risk of delivering a child with low birth weight [OR = 3.45 (95% CI = 1.25, 9.54)] compared to those who did use periconceptional folic acid supplements. No significant effects were observed for the risks of preterm birth and small-size-for-gestational-age at birth. Our results suggest that some adverse effects of maternal smoking on fetal growth and neonatal outcomes might be reduced by the use of folic acid supplements. The observed interaction seems to be mainly driven by smoking in the first trimester only.