The influence of folic acid supplement on the outcome of pregnancies in the county of Funen in Denmark

Maternal Folic Acid Supplementation, Dietary Folate Intake, and Low Birth Weight: A Birth Cohort Study

Objectives

To investigate the independent and collective effects of maternal folic acid supplementation or dietary folate intake on the risk of low birth weight (LBW), and to further comprehensively examine the joint associations of folic acid supplementation and dietary folate intake with LBW by various clinical subtypes.

Design

Participants were recruited from Gansu Provincial Maternity and Child Care Hospital. A standardized and structured questionnaire was distributed to collect demographic factors, reproductive and medical history, occupational and residential history, physical activity, and diet. Data on pregnancy-related complications and birth outcomes were extracted from medical records. Unconditional logistic regression models were used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) for single and joint associations of folic acid supplementation and dietary folate intake with LBW.

Setting

A birth cohort data analysis using the 2010–2012 Gansu Provincial Maternity and Child Care Hospital in Lanzhou, China.

Participants

In total, 9,231 pregnant women and their children were enrolled in the study.

Results

Compared with non-users, folic acid supplementation was associated with a reduced risk of LBW (OR: 0.80, 95% CI: 0.66–0.97), and the reduced risk was mainly seen for term-LBW (OR: 0.59, 95% CI: 0.41–0.85), and multiparous-LBW (OR: 0.72, 95% CI: 0.54–0.94). There were no significant associations between dietary folate intake and LBW, and there was no interaction between folic acid supplement and dietary folate intake on LBW.

Conclusions

Our study results indicated that folic acid supplementation was associated with a reduced risk of LBW, and there was no interaction between folic acid supplements and dietary folate intake on LBW.

Dietary Folate Intake and Folic Acid Supplements among Pregnant Women from Southern Italy: Evidence from the "Mamma & Bambino" Cohort

Folate requirement among women who plan to become pregnant should be raised to 600 μg/day during the periconceptional period. To meet this need, several countries began to promote the use of folic acid supplements before and during pregnancy. Here, we investigated prevalence and determinants of dietary folate intake and folic acid supplement use among 397 pregnant women (aged 15–50 years old, median = 37 years old). We also investigated their effects on neonatal outcomes in a subgroup of women who completed pregnancy. For doing that, we used data from the “Mamma & Bambino” project, an ongoing mother-child cohort settled in Catania (Italy). Inadequate folate intake was evaluated using a Food Frequency Questionnaire and defined as an intake < 600 μg/day. Women were also classified as non-users (i.e., women who did not use folic acid supplements), insufficient users (i.e., women who did not take folic acid supplements as recommended), and recommended users of folic acid supplements. Neonatal outcomes of interest were preterm birth (PTB) and small for gestational age (SGA). Nearly 65% of women (n = 257) reported inadequate folate intake, while 74.8% and 22.4% were respectively classified as insufficient or recommended users of supplements. We demonstrated higher odds of inadequate folate intake among smoking women (OR = 1.457; 95%CI = 1.046–2.030; p = 0.026), those who followed dietary restrictions (OR = 2.180; 95%CI = 1.085–4.378; p = 0.029), and those with low adherence to the Mediterranean Diet (OR = 3.194; 95%CI = 1.958–5.210; p < 0.001). In a subsample of 282 women who completed pregnancy, we also noted a higher percentage of SGA among those with inadequate folate intake (p < 0.001). Among 257 women with inadequate folate intake, those with low educational level were more likely to not take folic acid supplements than their more educated counterpart (OR = 5.574; 95%CI = 1.487–21.435; p = 0.012). In a subsample of 184 women with inadequate folate intake and complete pregnancy, we observed a higher proportion of SGA newborns among women who did not take supplement before pregnancy and those who did not take at all (p = 0.009). We also noted that the proportion of PTB was higher among non-users and insufficient users of folic acid supplements, but difference was not statistically significant. Our study underlined the need for improving the adherence of pregnant women with recommendations for dietary folate intake and supplement use. Although we proposed a protective effect of folic acid supplement use on risk of SGA, further research is encouraged to corroborate our findings and to investigate other factors involved.

Folic acid supplementation, dietary folate intake and risk of small for gestational age in China

OBJECTIVE

To investigate the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of small for gestational age (SGA) and to examine the joint effect of folic acid supplementation and dietary folate intake on the risk of SGA.

DESIGN

Participants were interviewed by trained study interviewers using a standardized and structured questionnaire. Information on birth outcomes and maternal complications was abstracted from medical records and dietary information was collected via a semi-quantitative FFQ before conception and during pregnancy.

SETTING

A birth cohort data analysis using the 2010-2012 Gansu Provincial Maternity and Child Care Hospital.

PARTICIPANTS

Women (n 8758) and their children enrolled in the study.

RESULTS

Folic acid supplementation was associated with a reduced risk of SGA (OR = 0·72, 95 % CI 0·60, 0·86), with the reduced risk seen mainly for SGA at ≥37 weeks of gestational age (OR = 0·70, 95 % CI 0·58, 0·85) and nulliparous SGA (OR = 0·67, 95 % CI 0·54, 0·84). There was no significant association between dietary folate intake and SGA risk.

CONCLUSIONS

Our study suggested that folic acid supplementation was associated with a reduced risk of SGA and the risk varied by preterm status and parity.

Impact of Periconceptional Folic Acid Supplementation on Low Birth Weight and Small-for-Gestational-Age Infants in China: A Large Prospective Cohort Study

OBJECTIVES

To explore the effects of maternal folic acid supplementation alone during pregnancy on the incidence of low birth weight (LBW) and small-for-gestational-age (SGA) infant status.

STUDY DESIGN

Data were derived from a large population-based cohort study performed in China to evaluate the prevention of neural tube defects with folic acid supplementation. The sample comprised 200 589 singleton live births registered in 2 southern Chinese provinces by mothers for whom detailed information on folic acid use was available. Gestational age was calculated from the first day of the last menstrual period. LBW was defined as a birth weight <2500 g. Infants were considered SGA when the age-adjusted birth weight was below the 10th percentile as defined by a national survey performed in 1998. Logistic regression was used to estimate the effects of folic acid after adjusting for the principal potential confounders.

RESULTS

The overall incidence of LBW and SGA status was 2.18% and 5.82%, respectively. The incidence of LBW and SGA status was 2.09% and 5.73% in women who took folic acid, and 2.27% and 5.90% in those who did not. The adjusted risk ratios associated with folic acid use were 0.85 (95% CI: 0.80-0.90) for LBW and 0.93 (95% CI: 0.89-0.96) for SGA status. Folic acid use during pregnancy appeared to be particularly important to prevent LBW and SGA status.

CONCLUSIONS

A maternal daily intake of 400 µg folic acid alone significantly reduced the risks of infant LBW and SGA status.

Safety and benefits of interventions to increase folate status in malaria-endemic areas

For decades, folic acid has routinely been given to prevent or treat anaemia in children, pregnant women and people with sickle cell disease. However, there is no conclusive evidence that folate deficiency anaemia constitutes a public health problem in any of these groups. Industrial flour fortification is recommended and implemented in many countries to combat neural tube defects. Dietary folates or folic acid can antagonise the action of antifolate drugs that play a critical role in the prevention and treatment of malaria. Randomised trials have shown that folic acid supplementation increases the rate of treatment failures with sulfadoxine-pyrimethamine. The efficacy of antifolate drugs against Plasmodium is maximized in the absence of exogenous folic acid, suggesting that there is no safe minimum dose of ingested folic acid. We here review the safety and benefits of interventions to increase folate status in malaria-endemic countries. We conclude that formal cost-benefit analyses are required.

Vitamin supplementation for preventing miscarriage

BACKGROUND

Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.

OBJECTIVES

The objectives of this review were to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (6 November 2015) and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing supplementation during pregnancy with one or more vitamins with either placebo, other vitamins, no vitamins or other interventions. We have included supplementation that started prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion, extracted data and assessed trial quality. We assessed the quality of the evidence using the GRADE approach. The quality of evidence is included for numerical results of outcomes included in the 'Summary of findings' tables.

MAIN RESULTS

We included a total of 40 trials (involving 276,820 women and 278,413 pregnancies) assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that was eligible for the review. Eight trials were cluster-randomised and contributed data for 217,726 women and 219,267 pregnancies in total.Approximately half of the included trials were assessed to have a low risk of bias for both random sequence generation and adequate concealment of participants to treatment and control groups. Vitamin C supplementation There was no difference in the risk of total fetal loss (risk ratio (RR) 1.14, 95% confidence interval (CI) 0.92 to 1.40, seven trials, 18,949 women; high-quality evidence); early or late miscarriage (RR 0.90, 95% CI 0.65 to 1.26, four trials, 13,346 women; moderate-quality evidence); stillbirth (RR 1.31, 95% CI 0.97 to 1.76, seven trials, 21,442 women; moderate-quality evidence) or adverse effects of vitamin supplementation (RR 1.16, 95% CI 0.39 to 3.41, one trial, 739 women; moderate-quality evidence) between women receiving vitamin C with vitamin E compared with placebo or no vitamin C groups. No clear differences were seen in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin C compared with placebo or no vitamin C groups. Vitamin A supplementation No difference was found in the risk of total fetal loss (RR 1.01, 95% CI 0.61 to 1.66, three trials, 1640 women; low-quality evidence); early or late miscarriage (RR 0.86, 95% CI 0.46 to 1.62, two trials, 1397 women; low-quality evidence) or stillbirth (RR 1.29, 95% CI 0.57 to 2.91, three trials, 1640 women; low-quality evidence) between women receiving vitamin A plus iron and folate compared with placebo or no vitamin A groups. There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of vitamin A compared with placebo or no vitamin A groups. Multivitamin supplementation There was evidence of a decrease in the risk for stillbirth among women receiving multivitamins plus iron and folic acid compared iron and folate only groups (RR 0.92, 95% CI 0.85 to 0.99, 10 trials, 79,851 women; high-quality evidence). Although total fetal loss was lower in women who were given multivitamins without folic acid (RR 0.49, 95% CI 0.34 to 0.70, one trial, 907 women); and multivitamins with or without vitamin A (RR 0.60, 95% CI 0.39 to 0.92, one trial, 1074 women), these findings included one trial each with small numbers of women involved. Also, they include studies where the comparison groups included women receiving either vitamin A or placebo, and thus require caution in interpretation.We found no difference in the risk of total fetal loss (RR 0.96, 95% CI 0.93 to 1.00, 10 trials, 94,948 women; high-quality evidence) or early or late miscarriage (RR 0.98, 95% CI 0.94 to 1.03, 10 trials, 94,948 women; moderate-quality evidence) between women receiving multivitamins plus iron and folic acid compared with iron and folate only groups.There was no evidence of differences in the risk of total fetal loss or miscarriage between women receiving any other combination of multivitamins compared with placebo, folic acid or vitamin A groups. Folic acid supplementation There was no evidence of any difference in the risk of total fetal loss, early or late miscarriage, stillbirth or congenital malformations between women supplemented with folic acid with or without multivitamins and/or iron compared with no folic acid groups. Antioxidant vitamins supplementation There was no evidence of differences in early or late miscarriage between women given antioxidant compared with the low antioxidant group (RR 1.12, 95% CI 0.24 to 5.29, one trial, 110 women).

AUTHORS' CONCLUSIONS

Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage. However, evidence showed that women receiving multivitamins plus iron and folic acid had reduced risk for stillbirth. There is insufficient evidence to examine the effects of different combinations of vitamins on miscarriage and miscarriage-related outcomes.

Folic acid supplementation: what is new? Fetal, obstetric, long-term benefits and risks

The association between folic acid supplementation, prior to conception and/or during pregnancy and pregnancy outcomes, has been the subject of numerous studies. The worldwide recommendation of folic acid is at least 0.4 mg daily for all women of reproductive age, and 4–5 mg in high-risk women. In addition, evidence shows that folic acid supplementation could modulate other adverse pregnancy outcomes, specifically, in pregnancies complicated by seizure disorders, preeclampsia, anemia, fetal growth restriction and autism. This review summarizes the available national and international guidelines, concerning the indications and dosage of folic acid supplementation during pregnancy. In addition, it describes the potential preventive benefits of folic acid supplementation on multiple maternal and fetal outcomes, as well as potential risks.

Effects and safety of periconceptional oral folate supplementation for preventing birth defects

BACKGROUND

It has been reported that neural tube defects (NTD) can be prevented with periconceptional folic acid supplementation. The effects of different doses, forms and schemes of folate supplementation for the prevention of other birth defects and maternal and infant outcomes are unclear.

OBJECTIVES

This review aims to examine whether periconceptional folate supplementation reduces the risk of neural tube and other congenital anomalies (including cleft palate) without causing adverse outcomes in mothers or babies. This is an update of a previously published Cochrane review on this topic.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2015). Additionally, we searched the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (31 August 2015) and contacted relevant organisations to identify ongoing and unpublished studies.

SELECTION CRITERIA

We included all randomised or quasi-randomised trials evaluating the effect of periconceptional folate supplementation alone, or in combination with other vitamins and minerals, in women independent of age and parity.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of studies against the inclusion criteria, extracted data from included studies, checked data entry for accuracy and assessed the risk of bias of the included studies. We assessed the quality of the body of evidence using the GRADE approach.

MAIN RESULTS

Five trials involving 7391 women (2033 with a history of a pregnancy affected by a NTD and 5358 with no history of NTDs) were included. Four comparisons were made: 1) supplementation with any folate versus no intervention, placebo or other micronutrients without folate (five trials); 2) supplementation with folic acid alone versus no treatment or placebo (one trial); 3) supplementation with folate plus other micronutrients versus other micronutrients without folate (four trials); and 4) supplementation with folate plus other micronutrients versus the same other micronutrients without folate (two trials). The risk of bias of the trials was variable. Only one trial was considered to be at low risk of bias. The remaining studies lacked clarity regarding the randomisation method or whether the allocation to the intervention was concealed. All the participants were blinded to the intervention, though blinding was unclear for outcome assessors in the five trials.The results of the first comparison involving 6708 births with information on NTDs and other infant outcomes, show a protective effect of daily folic acid supplementation (alone or in combination with other vitamins and minerals) in preventing NTDs compared with no interventions/placebo or vitamins and minerals without folic acid (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.17 to 0.58); five studies; 6708 births; high quality evidence). Only one study assessed the incidence of NTDs and showed no evidence of an effect (RR 0.07, 95% CI 0.00 to 1.32; 4862 births) although no events were found in the group that received folic acid. Folic acid had a significant protective effect for reoccurrence (RR 0.34, 95% CI 0.18 to 0.64); four studies; 1846 births). Subgroup analyses suggest that the positive effect of folic acid on NTD incidence and recurrence is not affected by the explored daily folic acid dosage (400 µg (0.4 mg) or higher) or whether folic acid is given alone or with other vitamins and minerals. These results are consistent across all four review comparisons.There is no evidence of any preventive or negative effects on cleft palate (RR 0.73, 95% CI 0.05 to 10.89; three studies; 5612 births; low quality evidence), cleft lip ((RR 0.79, 95% CI 0.14 to 4.36; three studies; 5612 births; low quality evidence), congenital cardiovascular defects (RR 0.57, 95% CI 0.24 to 1.33; three studies; 5612 births; low quality evidence), miscarriages (RR 1.10, 95% CI 0.94 to 1.28; five studies; 7391 pregnancies; moderate quality evidence) or any other birth defects (RR 0.94, 95% CI 0.53 to 1.66; three studies; 5612 births; low quality evidence). There were no included trials assessing the effects of this intervention on neonatal death, maternal blood folate or anaemia at term.

AUTHORS' CONCLUSIONS

Folic acid, alone or in combination with vitamins and minerals, prevents NTDs, but does not have a clear effect on other birth defects.

Folic acid supplementation, dietary folate intake and risk of preterm birth in China

PURPOSE

Folic acid supplementation has been suggested to reduce the risk of preterm birth. However, results from previous epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake during pre- and post-conception reduces the risk of preterm birth.

METHODS

We analyzed data from a birth cohort study conducted between 2010 and 2012 in Lanzhou, China, including 10,179 pregnant women with live singleton births.

RESULTS

Compared to non-users, folic acid supplement users with >12-week duration had a reduced risk of preterm birth (OR 0.67, 95 % CI 0.55-0.83) with a significant dose-response relationship (P for trend = 0.01). A similar pattern was observed for spontaneous preterm birth. Stronger associations were seen for ever use of folic acid supplement and very preterm birth (OR 0.50, 95 % CI 0.36-0.69) and spontaneous very preterm birth (OR 0.42, 95 % CI 0.29-0.63). Dietary folate intake during preconception and pregnancy were also associated with reduced risk of preterm birth (OR 0.68, 95 % CI 0.56-0.83, OR 0.57, 95 % CI 0.47-0.70 for the highest quartiles, respectively), particularly for spontaneous very preterm (OR 0.41, 95 % CI 0.24-0.72, OR 0.26, 95 % CI 0.15-0.47 for the highest quartiles, respectively). There were also decreased risks of preterm birth observed per 10-µg increase in dietary folate intake, and similar associations were found after stratification by folic acid supplementation status.

CONCLUSIONS

Our results suggest that folic acid supplementation and higher dietary folate intake during preconception and pregnancy reduces the risk of preterm birth, and the protective effect varies by preterm subtypes.

Effectiveness of folic acid supplementation in pregnancy on reducing the risk of small-for-gestational age neonates: a population study, systematic review and meta-analysis

OBJECTIVES

To assess the effect of timing of folic acid (FA) supplementation during pregnancy on the risk of the neonate being small for gestational age (SGA).

DESIGN

A population database study and a systematic review with meta-analysis including the results of this population study.

SETTING AND DATA SOURCES

A UK regional database was used for the population study and an electronic literature search (from inception until August 2013) for the systematic review.

PARTICIPANTS AND INCLUDED STUDIES

Singleton live births with no known congenital anomalies; 111,736 in population study and 188,796 in systematic review.

OUTCOME MEASURES, DATA EXTRACTION AND ANALYSIS

The main outcome was SGA based on customised birthweight centile. Associations are presented as odds ratios (OR) and adjusted odds ratios (aOR), adjusted for maternal and pregnancy-related characteristics.

RESULTS

Of 108,525 pregnancies with information about FA supplementation, 92,133 (84.9%) had taken FA during pregnancy. Time of commencement of supplementation was recorded in 39,416 pregnancies, of which FA was commenced before conception in 10,036, (25.5%) cases. Preconception commencement of FA supplementation was associated with reduced risk of SGA <10th centile (aOR 0.80, 95% CI 0.71-0.90, P < 0.01) and SGA <5th centile (aOR 0.78, 95% CI 0.66-0.91, P < 0.01). This result was reproduced when the data were pooled with other studies in the systematic review, showing a significant reduction in SGA (<5th centile) births with preconception commencement of FA (aOR 0.75, 95% CI 0.61-0.92, P < 0.006). In contrast, postconception folate had no significant effect on SGA rates.

CONCLUSION

Supplementation with FA significantly reduces the risk of SGA at birth but only if commenced preconceptually independent of other risk factors.

SYSTEMATIC REVIEW REGISTRATION

This systematic review was prospectively registered with PROSPERO number CRD42013004895.

Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study

BACKGROUND

Health authorities in numerous countries recommend periconceptional folic acid supplementation to prevent neural tube defects. The objective of this study was to examine the association of dietary folate intake and folic acid supplementation during different periods of pregnancy with the risk of spontaneous preterm delivery (PTD).

METHODS

The Norwegian Mother and Child Cohort Study is a population-based prospective cohort study. A total of 66,014 women with singleton pregnancies resulting in live births in 2002-2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until pregnancy week 24. At gestational week 22, the women completed a food frequency questionnaire, which allowed the calculation of their average total folate intake from foods and supplements for the first 4-5 months of pregnancy. Spontaneous PTD was defined as the spontaneous onset of delivery between weeks 22+0 and 36+6 (n = 1,755).

RESULTS

The median total folate intake was 313 μg/d (interquartile range IQR 167-558) in the overall population and 530 μg/d (IQR 355-636) in the supplement users. Eighty-five percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while only 44% initiated folic acid supplementation before pregnancy. Cox regression analysis showed that the amount of dietary folate intake (hazard ratio HR 1.00; confidence interval 95% CI 0.61-1.65) and supplemental folate intake (HR 1.00; CI 1.00-1.00) was not significantly associated with the risk of PTD. The initiation of folic acid supplementation more than 8 weeks before conception was associated with an increased risk for spontaneous PTD (HR 1.18; CI 1.05-1.32) compared to no folic acid supplementation preconception. There was no significant association with PTD when supplementation was initiated within 8 weeks preconception (HR 0.99; CI 0.87-1.13). All analyses were adjusted for maternal characteristics and socioeconomic, health and dietary variables.

CONCLUSIONS

Our findings do not support a protective effect of dietary folate intake or folic acid supplementation on spontaneous PTD. Preconceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of spontaneous PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.

Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study

Background

Health authorities in numerous countries recommend periconceptional folic acid to pregnant women to prevent neural tube defects. The objective of this study was to examine the association of folic acid supplementation during different periods of pregnancy and of dietary folate intake with the risk of spontaneous preterm delivery (PTD).

Methods

The Norwegian Mother and Child Cohort Study is a population-based prospective cohort study. A total of 65,668 women with singleton pregnancies resulting in live births in 1999–2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until week 24 during pregnancy. At gestational week 22, the women completed a food frequency questionnaire, which allowed the calculation of their average total folate intake from foods and supplements for the first 4–5 months of pregnancy. Spontaneous PTD was defined as the spontaneous onset of delivery between weeks 22⁺⁰ and 36⁺⁶ (n = 1,628).

Results

The median total folate intake was 266 μg/d (interquartile range IQR 154–543) in the overall population and 540 μg/d (IQR 369–651) in the supplement users. Eighty-three percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while 42% initiated folic acid supplementation before their pregnancy. Cox regression analysis showed that the amount of folate intake from the diet (hazard ratio HR 1.16; confidence interval CI 0.65-2.08) and from the folic acid supplements (HR 1.04; CI 0.95-1.13) was not significantly associated with the risk of PTD. The initiation of folic acid supplementation more than 8 weeks before conception was associated with an increased risk for PTD (HR 1.19; CI 1.05-1.34) compared to no folic acid supplementation pre-conception. There was no significant association with PTD when supplementation was initiated within 8 weeks pre-conception (HR 1.01; CI 0.88-1.16). All analyses were adjusted for maternal characteristics and socioeconomic, health and dietary variables.

Conclusions

Our findings do not support a protective effect of dietary folate intake or folic acid supplementation on spontaneous PTD. Pre-conceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.

Influence of maternal folate status on human fetal growth parameters

Worldwide periconceptional folic acid supplement use is recommended to prevent neural tube defects. This also stimulated research on maternal folate status in association with fetal growth, an important predictor of perinatal and future development and health. We provide an overview of literature on associations between maternal folate status during pregnancy determined by folate biomarker concentrations in blood, folic acid supplement use and dietary folate intake, and fetal growth parameters. Literature was searched in PubMed up to November 2011. Some studies suggest inverse associations between serum folate, folic acid supplement use and dietary folate intake and risk of a low birth weight or small for gestational age infant. The strongest evidence, however, revealed positive associations between birth weight and red blood cell folate, folic acid supplement use and dietary folate intake. Red blood cell folate appeared to be most consistently associated with other fetal growth parameters. These findings contribute to the knowledge of the impact of maternal folate status on fetal growth, and subsequently perinatal health and disease risks in later life. Future research is recommended to examine effects of windows, duration and dose of folic acid supplement use and use of folate-rich dietary patterns in different populations on fetal growth parameters.

The effect of high doses of folic acid and iron supplementation in early-to-mid pregnancy on prematurity and fetal growth retardation: the mother-child cohort study in Crete, Greece (Rhea study)

PURPOSE

We examined whether high doses of folic acid and iron supplementation in early-to-mid pregnancy affect the risk of preterm birth, low birth weight, and small for gestational age neonates, in the mother-child cohort in Crete, Greece (Rhea study).

METHODS

We included 1,279 women with singleton pregnancies with complete data on supplements use in early-to-mid pregnancy and birth outcomes. Anthropometric measurements at birth were obtained from medical records. Red blood cell folate concentrations in cord blood were measured in a subsample of the study population (n = 58).

RESULTS

Sixty-six percent of the study participants reported high doses of supplemental folic acid use (5 mg/day), while 21 % reported excessive doses of folic acid use (>5 mg/day) in early-to-mid pregnancy. Daily intake of 5-mg supplemental folic acid was associated with a 31 % decrease in the risk of preterm birth (RR, 0.69; 95 % CI, 0.44, 0.99), 60 % decrease in the risk of delivering a low birth weight neonate (RR, 0.40; 95 % CI, 0.21, 0.76), and 66 % decrease in the risk of delivering a small for gestational age (SGA) neonate (RR, 0.34; 95 % CI, 0.16, 0.73). Daily doses of iron supplementation more than 100 mg were associated with a twofold increased risk for SGA neonates (RR, 2.14; 95 % CI, 0.99, 5.97).

CONCLUSION

These findings suggest that high daily doses of supplementary folic acid in early-to-mid pregnancy may be protective for preterm birth, low birth weight, and small for gestational age neonates, while high daily doses of supplementary iron may be harmful for fetal growth.

The effects of homocysteine and folic acid on angiogenesis and VEGF expression during chicken vascular development

Homocysteine (Hcy) has been implicated in the development of cardiovascular developmental defects. Additionally, in experimental studies, vasculotoxic properties of Hcy have been described. Although Hcy has been identified as a vascular pathogen, little is known about the direct effects Hcy exerts during early embryonic vascular development. Angiogenesis is a critical process involved in embryo survival and development. There are limited studies on the effects of Hcy on early embryonic vasculogenesis and angiogenesis. Folic acid (FA) is a B vitamin essential in embryo development, and FA supplementation may lead to reduced Hcy levels. Therefore, the purpose of our study was to explore the effects of Hcy and FA on early embryonic vascular development. Embryonic day (E) 3.5 chicken embryos were treated with a sham, Hcy or FA solution. We developed a computational program for systematic analysis of microscopic images obtained from the extra embryonic vascular beds. These results were combined with real-time PCR data on the expression of VEGF-A and its receptor in these vascular beds. Our data show that Hcy exposure inhibits early vascular development, displayed by a significant reduction of vessel area and altered composition of the vascular beds. Vascular beds of Hcy embryos for the greater part consisted of vessels of the smallest diameters, compared to middle size vessels in control and FA embryos. Hcy also reduced expression of VEGF-A and VEGFR-2. No significant effects of FA were found. We conclude that Hcy exposure causes impaired early extra embryonic vascular development, shown by altered composition of the vascular beds as well as reduced expression of VEGF-A and VEGFR-2. These effects of Hcy, and the consecutive cascade of events, may be involved in the development of cardiovascular developmental defects.

Maternal serum folate species in early pregnancy and lower genital tract inflammatory milieu

OBJECTIVE

We previously reported that elevated antiinflammatory cervical cytokines in early pregnancy were associated with spontaneous preterm birth. Our objective was to explore the relation between serum folate vitamers and the lower genital tract inflammatory milieu.

STUDY DESIGN

Pregnant women (n = 417) at <16 weeks' gestation had serum samples that were analyzed for folate species 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, and cervical fluid that was assayed for cytokine concentrations. Patterns in proinflammatory cytokines (interleukin [IL]-1β, -6, -8, and -10; monocyte chemotactic protein-1) and antiinflammatory cytokines (IL-4, IL-10, IL-13) were identified with factor analysis.

RESULTS

After confounder adjustment, maternal serum 5-methyltetrahydrofolate concentrations had a strong negative association with elevated antiinflammatory scores; serum 5-formyltetrahydrofolate concentrations were associated positively with elevated antiinflammatory scores (both P < .05). Maternal folate was not associated with proinflammatory scores.

CONCLUSION

Maternal serum folate vitamers are associated with cervical cytokine concentrations, which suggests a possible mechanistic link between folate and preterm birth risk.

Periconceptional folic acid supplementation and anthropometric measures at birth in a cohort of pregnant women in Valencia, Spain

We examined the relationship between dietary folate intake and periconceptional use of folic acid (FA) supplements, and small-for-gestational age for weight (SGA-W) and height (SGA-H). The study is based on 786 Spanish women aged 16 years or above, who attended the first-term prenatal population-based screening programme (10-13 weeks) at the reference hospital 'La Fe', Valencia, with singleton pregnancy. Periconceptional use of FA supplements was categorised as non-users, moderate users ( ≤ 1 mg/d) and high users (>1 mg/d). Babies born to mothers who used high doses of FA supplements had a significant reduction in mean birth height compared with babies of non-users (β = - 0·53, 95 % CI - 0·96, - 0·09). As regards weight, mothers using moderate and high doses of FA supplements had lower-birth-weight babies for gestational age than non-users (β = - 22·96, 95 % CI - 101·14, 55·23; β = - 89·72, 95 % CI - 188·64, 9·21, respectively), although these decreases were not significant. Results from the multivariate logistic regression models showed that high FA supplement users had a higher significant risk for SGA-H (OR 5·33, 95 % CI 2·08, 13·7), and that users of moderate doses were not associated with a higher risk of either a SGA-W or a SGA-H baby. In contrast, increased quintiles of the dietary intake of folate were associated with a decreased risk of SGA-W (P for trend = 0·002), although no association was observed for SGA-H. Our findings suggest that periconceptional use of FA supplements greater than 1 mg/d is associated with decreased birth height and may entail a risk of decreased birth weight.

Vitamin supplementation for preventing miscarriage

BACKGROUND

Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.

OBJECTIVES

The objectives of this review are to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage, maternal adverse outcomes and fetal and infant adverse outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (21 June 2010).

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing one or more vitamins with either placebo, other vitamins, no vitamins or other interventions, prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trials for inclusion, extracted data and assessed trial quality.

MAIN RESULTS

We identified 28 trials assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that was eligible for the review. Overall, the included trials involved 96,674 women and 98,267 pregnancies. Three trials were cluster randomised and combined contributed data for 62,669 women and 64,210 pregnancies in total. No significant differences were seen between women taking any vitamins compared with controls for total fetal loss (relative risk (RR) 1.04, 95% confidence interval (CI) 0.95 to 1.14), early or late miscarriage (RR 1.09, 95% CI 0.95 to 1.25) or stillbirth (RR 0.86, 95% CI 0.65 to 1.13) and most of the other primary outcomes, using fixed-effect models. Compared with controls, women given any type of vitamin(s) pre or peri-conception were more likely to have a multiple pregnancy (RR 1.38, 95% CI 1.12 to 1.70, three trials, 20,986 women).

AUTHORS' CONCLUSIONS

Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage or stillbirth. However, women taking vitamin supplements may be more likely to have a multiple pregnancy. There is insufficient evidence to examine the effects of different combinations of vitamins on miscarriage, stillbirth or other maternal and infant outcomes.

Effects and safety of periconceptional folate supplementation for preventing birth defects

BACKGROUND

It has been reported that neural tube defects can be prevented with periconceptional folic acid supplementation. The effects of different doses, forms and schemes of folate supplementation for the prevention of other birth defects and maternal and infant outcomes are unclear.

OBJECTIVES

This review updates and expands a previous Cochrane Review assessing the effects of periconceptional supplementation with folic acid to reduce neural tube defects (NTDs). We examined whether folate supplementation before and during early pregnancy can reduce neural tube and other birth defects (including cleft palate) without causing adverse outcomes for mothers or babies.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010). Additionally, we searched the international clinical trials registry platform and contacted relevant organisations to identify ongoing and unpublished studies.

SELECTION CRITERIA

We included all randomised or quasi-randomised trials evaluating the effect of periconceptional folate supplementation alone, or in combination with other vitamins and minerals, in women independent of age and parity.

DATA COLLECTION AND ANALYSIS

We assessed trials for methodological quality using the standard Cochrane criteria. Two authors independently assessed the trials for inclusion, one author extracted data and a second checked for accuracy.

MAIN RESULTS

Five trials involving 6105 women (1949 with a history of a pregnancy affected by a NTD and 4156 with no history of NTDs) were included. Overall, the results are consistent in showing a protective effect of daily folic acid supplementation (alone or in combination with other vitamins and minerals) in preventing NTDs compared with no interventions/placebo or vitamins and minerals without folic acid (risk ratio (RR) 0.28, 95% confidence interval (CI) 0.15 to 0.52). Only one study assessed the incidence of NTDs and the effect was not statistically significant (RR 0.08, 95% CI 0.00 to 1.33) although no events were found in the group that received folic acid. Folic acid had a significant protective effect for reoccurrence (RR 0.32, 95% CI 0.17 to 0.60). There is no statistically significant evidence of any effects on prevention of cleft palate, cleft lip, congenital cardiovascular defects, miscarriages or any other birth defects. There were no included trials assessing the effects of this intervention on maternal blood folate or anaemia at term.We found no evidence of short-term side effects.

AUTHORS' CONCLUSIONS

Folic acid, alone or in combination with vitamins and minerals, prevents NTDs but does not have a clear effect on other birth defects.

Maternal serum folate species in early pregnancy and risk of preterm birth

BACKGROUND

Poor maternal folate status has been associated with an increased risk of preterm birth. However, major gaps remain in our understanding of how individual folate species relate to preterm birth.

OBJECTIVE

Our objective was to assess the association between maternal folate status as measured by 5-methyltetrahydrofolate (5MeTHF), 5-formyltetrahydrofolate (5FoTHF), and folic acid concentrations, which are the 3 primary folate species in serum, and the risk of preterm birth and spontaneous preterm birth (sPTB).

DESIGN

A cohort of 313 pregnant women who received care at resident antepartum clinics at Magee-Womens Hospital (Pittsburgh, PA) (2003-2007) was enrolled at <16 wk gestation. We analyzed nonfasting blood samples that were drawn from subjects at enrollment for the 3 folate species by using HPLC-tandem mass spectrometry.

RESULTS

Serum 5MeTHF and 5FoTHF concentrations comprised 65% and 33% of total folate concentrations, respectively. In confounder-adjusted, multivariable, log-binomial regression models, 1-SD increases in serum total folate and serum 5MeTHF concentrations were associated with significant reductions in the risk of sPTB (P < 0.05). There was a significant interaction between serum 5MeTHF and 5FoTHF concentrations and risk of preterm birth (P = 0.01). When serum 5MeTHF concentrations were low, there was a positive linear relation between 5FoTHF and risk of preterm birth. When 5MeTHF concentrations were high, there was a strong negative relation between 5FoTHF and preterm birth.

CONCLUSIONS

Our results imply that the relative concentrations of folate species may be more critical than total folate in preventing preterm birth. An improved understanding of folate metabolism during pregnancy may lead to targeted intervention strategies that decrease the rate of preterm birth.

Gestational nutrition improves outcomes of vaginal deliveries in Jordan: an epidemiologic screening

Adequate and balanced nutrition during gestation is essential for achieving healthy pregnancy outcomes. This retrospective survey tested the hypothesis that maternal nutrition (macronutrients intake, micronutrients intake, and weight gain) during gestation will impact gestational outcomes (gestational age, birth weight, and labor spontaneity). The objectives of this study were to test the impact of macronutrients and micronutrients consumed during gestation, pregestational weight and weight gain during gestation on gestational age, birth weight, and labor spontaneity among Jordanian women. Study participants (n = 700) were recruited from a women's hospital in northern Jordan. Data were collected using structured interviews. Dietary determinants examined in the study included daily intake of macronutrients (energy, carbohydrate, protein, fat, and n-3 and n-6 fatty acids) and micronutrients (zinc, calcium, folate, vitamin C, vitamin A, and vitamin B6), pregestational body mass index, total weight gain, and weight gain pattern during pregnancy. Dietary data were obtained from a semiquantitative food frequency questionnaire. Mean (SEM) daily intakes of energy, carbohydrate, and protein were 10894 (138) Kj, 320 (3.8) g, and 90 (0.95) g, respectively; with fat contributing 36% of total energy. Average daily energy and carbohydrate intake during pregnancy were related negatively to gestational age (P < .05). Pregestational body mass index was associated positively with gestational age and birth weight (P < .05). Intakes of vitamin A and calcium had significant relationships with birth weight. Daily intakes of zinc, calcium, vitamin B6, and n-3 and n-6 fatty acids were associated with labor spontaneity. Dietary factors consumed during pregnancy are associated with pregnancy outcomes.

Infant birth size is not associated with maternal intake and status of folate during the second trimester in Norwegian pregnant women

Maternal folate status and smoking are potentially strong risk factors for infant birth size. We assessed the association of several folate indicators and smoking with birth outcomes in a subsample of participants in the Norwegian Mother and Child Cohort Study, consisting of 2934 singleton pregnancies in 2002-2003. Blood plasma folate and cotinine concentrations and self-reported intake of food folate and supplemental folic acid were measured during the second trimester (median 18 wk). Birth outcomes included gestational age, infant birth weight, head circumference, crown-heel length, and small for gestational age (SGA). Mean total dietary folate intake from foods (mean 268.0 microg/d) and supplements (mean 187.7 microg/d) was 455.7 microg/d. Smokers (plasma cotinine > or = 85 nmol/L) had substantially lower supplemental folic acid intake than nonsmokers, but they did not differ regarding folate intake from food only. Nevertheless, smoking was correlated with plasma folate both before and after adjusting for total dietary folate intake (both P < 0.001). We found no significant associations of food folate intake, supplemental folic acid use, total dietary folate intake, or plasma folate with the various birth outcomes after adjustment for potential confounders. Consistent with previous studies, infant birth size was strongly predicted by maternal smoking (adjusted odds ratio for SGA: 2.3; 95% CI: 1.6, 3.3). This study of well-nourished Norwegian pregnant women suggests that dietary folate and plasma folate during the second trimester are not risk factors for infant birth size.

Methylenetetrahydrofolate reductase ( MTHFR) C677T, A1298C and G1793A genotypes, and the relationship between maternal folate intake, tibia lead and infant size at birth

Small size at birth continues to be a problem worldwide and many factors, including reduced folate intake and Pb exposure, are associated with it. However, single factors rarely explain the variability in birth weight, suggesting a need for more complex explanatory models. We investigated environment-gene interactions to understand whether folate intake and maternal Pb exposure were associated with smaller newborn size in 474 women with uncomplicated pregnancies delivering term infants in Mexico City. We examined if folate intake modified the negative effects of maternal Pb burden on birth size. We also asked if maternal and infant methylenetetrahydrofolate reductase (MTHFR) genotypes (C677T, A1298C and G1793A) modified the effects of folate intake or Pb exposure on birth size. Women were aged 24.6 (sd 5.1) years; 43.5 % were primiparous. Maternal blood Pb at delivery was 86 (sd 42) microg/l, with 26.7 % having levels > or = 100 microg/l. Tibia Pb level was 9.9 (SD 9.8) microg/g. Of the women, 35.3 % had folate intakes < 400 microg/d. Birth weight was 3170 (SD 422) g. In covariate-adjusted regressions, higher folate intake was associated with higher birth weight (beta 0.04; P < 0.05). Higher bone Pb was associated with lower birth weight (beta - 4.9; P < 0.05). Folate intake did not modify the effects of Pb on birth size, nor did MTHFR modify the association between Pb or folate intake on birth size. Although modest, the relationship between maternal nutrition, Pb burden and birth size does underscore the importance of environmental exposures to child health because patterns of fetal growth may affect health outcomes well into adulthood.

Periconception folic acid supplementation, fetal growth and the risks of low birth weight and preterm birth: the Generation R Study

Countries worldwide, including the Netherlands, recommend that women planning pregnancy use a folic acid supplement during the periconception period. Some countries even fortify staple foods with folic acid. These recommendations mainly focus on the prevention of neural tube defects, despite increasing evidence that folic acid may also influence birth weight. We examined whether periconception folic acid supplementation affects fetal growth and the risks of low birth weight, small for gestational age (SGA) and preterm birth, in the Generation R Study in Rotterdam, the Netherlands. Main outcome measures were fetal growth measured in mid- and late pregnancy by ultrasound, birth weight, SGA and preterm birth in relation to periconception folic supplementation (0.4-0.5 mg). Data on 6353 pregnancies were available. Periconception folic acid supplementation was positively associated with fetal growth. Preconception folic acid supplementation was associated with 68 g higher birth weight (95 % CI 37.2, 99.0) and 13 g higher placental weight (95 % CI 1.1, 25.5), compared to no folic acid supplementation. In these analyses parity significantly modified the effect estimates. Start of folic acid supplementation after pregnancy confirmation was associated with a reduced risk of low birth weight (OR 0.61, 95 % CI 0.40, 0.94). Similarly, reduced risks for low birth weight and SGA were observed for women who started supplementation preconceptionally, compared to those who did not use folic acid (OR 0.43, 95 % CI 0.28, 0.69 and OR 0.40, 95 % CI 0.22, 0.72). In conclusion, periconception folic acid supplementation is associated with increased fetal growth resulting in higher placental and birth weight, and decreased risks of low birth weight and SGA.

Changes in haemostasis during normal pregnancy: does homocysteine play a role in maintaining homeostasis?

Homocysteine, derived from the demethylation of the ammo acid methionine, is either further catabolised by trans-sulfuration to cysteine or remethylated to methionine. Remethylation to methionine requires the cofactors, folate and vitamin B12. Folate is an effective homocysteine-lowering agent and, thus, homocysteine and folate status are inversely related. Hyperhomocysteinaemia is a strong independent risk factor for venous thromboembolism (VTE) and is associated with adverse pregnancy outcomes such as pre-eclampsia, placental abruption, early pregnancy loss and neural-tube defects. Pregnancy is a risk factor for VTE as a result of prothrombotic changes in levels of haemostatic factors. However, despite this hypercoagulable state, the incidence of pregnancy-associated VTE is relatively low. Hyperhomocysteinaemia is associated with abnormalities in markers of coagulation activation, and recent research suggests that folic acid supplementation, as well as lowering homocysteine, lowers markers of coagulation activation and increases levels of coagulation inhibitors. Tissue factor (TF) is the initiator of blood coagulationin vivo, and homocysteine induces TF expressionin vitro. During pregnancy, monocyte TF expression is lower than that in the non-pregnant state, and this lowering of TF may act to counterbalance increases in coagulation activation. Furthermore, despite a high folate requirement, several studies have reported that homocysteine is lower in normal pregnancy than in the non-pregnant state. Although the exact mechanism of homocysteine lowering during pregnancy is unclear, one possible outcome of lower homocysteine may be the protection of women from pregnancy complications and VTE, and thus lower homocysteine may contribute to maintaining homeostasis in haemostasis.

Folate and human reproduction

The influence of folate nutritional status on various pregnancy outcomes has long been recognized. Studies conducted in the 1950s and 1960s led to the recognition of prenatal folic acid supplementation as a means to prevent pregnancy-induced megaloblastic anemia. In the 1990s, the utility of periconceptional folic acid supplementation and folic acid food fortification emerged when they were proven to prevent the occurrence of neural tube defects. These distinctively different uses of folic acid may well be ranked among the most significant public health measures for the prevention of pregnancy-related disorders. Folate is now viewed not only as a nutrient needed to prevent megaloblastic anemia in pregnancy but also as a vitamin essential for reproductive health. This review focuses on the relation between various outcomes of human reproduction (ie, pregnancy, lactation, and male reproduction) and folate nutrition and metabolism, homocysteine metabolism, and polymorphisms of genes that encode folate-related enzymes or proteins, and we identify issues for future research.

Vitamin supplementation for preventing miscarriage

BACKGROUND

Miscarriage is a common complication of pregnancy that can be caused by a wide range of factors. Poor dietary intake of vitamins has been associated with an increased risk of miscarriage, therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage.

OBJECTIVES

The objectives of this review are to determine the effectiveness and safety of any vitamin supplementation, on the risk of spontaneous miscarriage, maternal adverse outcomes and fetal and infant adverse outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (8 September 2004), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003) and MEDLINE (1966 to May 2003), Current Contents (1998 to May 2003) and EMBASE (1980 to May 2003).

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing one or more vitamins with either placebo, other vitamins, no vitamins or other interventions, prior to conception, periconceptionally or in early pregnancy (less than 20 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data and assessed trial quality.

MAIN RESULTS

We identified seventeen trials assessing supplementation with any vitamin(s) starting prior to 20 weeks' gestation and reporting at least one primary outcome that were eligible for the review. Overall, the included trials involved 35,812 women and 37,353 pregnancies. Two trials were cluster randomised and contributed data for 20,758 women and 22,299 pregnancies in total. No difference was seen between women taking any vitamins compared with controls for total fetal loss (relative risk (RR) 1.05, 95% confidence interval (CI) 0.95 to 1.15), early or late miscarriage (RR 1.08, 95% CI 0.95 to 1.24) or stillbirth (RR 0.85, 95% CI 0.63 to 1.14) and most of the other primary outcomes, using fixed-effect models. For the other primary outcomes, women given any type of vitamin(s) compared with controls were less likely to develop pre-eclampsia (RR 0.68, 95% CI 0.54 to 0.85, four trials, 5580 women) and more likely to have a multiple pregnancy (RR 1.38, 95% CI 1.12 to 1.70, three trials, 20,986 women).

AUTHORS' CONCLUSIONS

Taking vitamin supplements, alone or in combination with other vitamins, prior to pregnancy or in early pregnancy, does not prevent women experiencing miscarriage or stillbirth. However, women taking vitamin supplements may be less likely to develop pre-eclampsia and more likely to have a multiple pregnancy.

Community-based interventions for improving perinatal and neonatal health outcomes in developing countries: a review of the evidence

BACKGROUND

Infant and under-5 childhood mortality rates in developing countries have declined significantly in the past 2 to 3 decades. However, 2 critical indicators, maternal and newborn mortality, have hardly changed. World leaders at the United Nations Millennium Summit in September 2000 agreed on a critical goal to reduce deaths of children <5 years by two thirds, but this may be unattainable without halving newborn deaths, which now comprise 40% of all under-5 deaths. Greater emphasis on wide-scale implementation of proven, cost-effective measures is required to save women's and newborns' lives. Approximately 99% of neonatal deaths take place in developing countries, mostly in homes and communities. A comprehensive review of the evidence base for impact of interventions on neonatal health and survival in developing-country communities has not been reported.

OBJECTIVE

This review of community-based antenatal, intrapartum, and postnatal intervention trials in developing countries aimed to identify (1) key behaviors and interventions for which the weight of evidence is sufficient to recommend their inclusion in community-based neonatal care programs and (2) key gaps in knowledge and priority areas for future research and program learning.

METHODS

Available published and unpublished data on the impact of community-based strategies and interventions on perinatal and neonatal health status outcomes were reviewed. Evidence was summarized systematically and categorized into 4 levels of evidence based on study size, location, design, and reported impact, particularly on perinatal or neonatal mortality. The evidence was placed in the context of biological plausibility of the intervention; evidence from relevant developed-country studies; health care program experience in implementation; and recommendations from the World Health Organization and other leading agencies.

RESULTS

A paucity of community-based data was found from developing-country studies on health status impact for many interventions currently being considered for inclusion in neonatal health programs. However, review of the evidence and consideration of the broader context of knowledge, experience, and recommendations regarding these interventions enabled us to categorize them according to the strength of the evidence base and confidence regarding their inclusion now in programs. This article identifies a package of priority interventions to include in programs and formulates research priorities for advancing the state of the art in neonatal health care.

CONCLUSIONS

This review emphasizes some new findings while recommending an integrated approach to safe motherhood and newborn health. The results of this study provide a foundation for policies and programs related to maternal and newborn health and emphasizes the importance of health systems research and evaluation of interventions. The review offers compelling support for using research to identify the most effective measures to save newborn lives. It also may facilitate dialogue with policy makers about the importance of investing in neonatal health.

Maternal Homocysteine before Conception and throughout Pregnancy Predicts Fetal Homocysteine and Birth Weight

Background: Increased homocysteine has been associated with pregnancy complications.

Methods: We investigated prospectively the effect of maternal homocysteine on normal pregnancy outcome. The study included 93 women and their offspring; 39 of the women took folic acid during the second and/or third trimesters of pregnancy. We measured homocysteine at preconception; at weeks 8, 20, and 32 of pregnancy; during labor; and in the fetal cord; we also recorded birth weight.

Results: Geometric mean (SE) maternal total homocysteine (tHcy) increased between 32 weeks of pregnancy and labor [7.98 (1.05) μmol/L in unsupplemented women and 6.26 (1.07) μmol/L in supplemented women; P &lt;0.0001 for both]. Fetal tHcy was lower than maternal tHcy [6.39 (1.06) μmol/L in unsupplemented pregnancies (P &lt;0.0001), and 5.18 (1.06) μmol/L in supplemented pregnancies (P &lt;0.05)]. Maternal tHcy was correlated from preconception throughout pregnancy (8 weeks, r = 0.708; 20 weeks, r = 0.637; 32 weeks, r = 0.537; labor, r = 0.502; P &lt;0.0001 for all time points) and with fetal tHcy [preconception, r = 0.255 (P &lt;0.05); 8 weeks, r = 0.321 (P &lt;0.01); 20 weeks, r = 0.469; 32 weeks, r = 0.550; labor, r = 0.624 (P &lt;0.0001)]. Mothers in the highest tHcy tertile at 8 weeks of pregnancy were three times [odds ratio, 3.26 (95% confidence interval, 1.05–10.13); P &lt;0.05] and at labor were four times [3.65 (1.15–11.56); P &lt;0.05] more likely to give birth to a neonate in the lowest birth weight tertile. Neonates of mothers in the highest tHcy tertile at labor weighed, on average, 227.98 g less than those of mothers in the low and medium tertiles (P = 0.014).

Conclusions: Supplemented mothers had lower tHcy at labor than unsupplemented mothers, as did their neonates. Maternal and fetal tHcy was significantly correlated throughout the study. Neonates of mothers in the highest tertile of homocysteine weighed less.

Occurrence of low birthweight and preterm delivery among California infants before and after compulsory food fortification with folic acid

OBJECTIVES

Studies suggest that folic acid intake influences the occurrence of low birthweight and preterm delivery. Since 1998, there has been compulsory fortification of flour and other grains with folic acid in the U.S. The objective of this study was to investigate the frequencies of low birthweight and preterm delivery after mandatory folic acid fortification among approximately six million California births.

METHODS

The authors investigated prevalences of low birthweight and preterm delivery before and after compulsory fortification among 5,916,630 singleton California live births that occurred from January 1990 through December 2000.

RESULTS

The unadjusted prevalences of very low birthweight, low birthweight, and preterm delivery did not substantially vary across birth years. That is, substantial decreased prevalences during the fortification period relative to the period preceding it were not observed. However, analyses that simultaneously adjusted for maternal age, parity, race/ethnicity, education, year of birth, and fortification period revealed the following relative risk ratios (RR) and 95% confidence intervals (CI): RR = 0.91, CI 0.88, 0.94 for very low birthweight, RR = 0.94; 95% CI 0.93, 0.96 for low birthweight, and RR = 0.96; 95% CI 0.94, 0.97 for preterm delivery.

CONCLUSION

Findings indicate small reductions in prevalences of these outcomes associated with the timing of fortification of the U.S. food supply.

Preterm delivery: an overview

Preterm delivery is the leading factor causing neonatal mortality and morbidity. We have conducted a PubMed literature search to obtain an update on the etiology, diagnostic problems and therapeutic considerations of preterm delivery. Approximately 5-10% of all births are premature. Preterm labor is associated with preterm rupture of membranes, cervical incompetence, polyhydramnion, fetal and uterine anomalies, infections, social factors, stress, smoking, heavy work and other risk factors. The diagnosis is made on the patients presenting symptoms, clinical findings and of progressive effacement and dilatation of the cervix. Biochemical markers of preterm delivery are of minor importance in daily clinical work. Measurement of the cervix, however, is a practical and valuable tool to predict preterm delivery. Cervical cerclage can be useful in selected cases. Antibiotics may help to prevent preterm labor in cases of known etiologic agents (e.g. preterm rupture of membranes and urinary infection). The use of tocolytic agents such as beta-sympathetic receptor stimulators can be advocated for a few days. There is evidence that their long-term use is not beneficial and could even be harmful to the fetus. Calcium channel blockers (nifedipine) and a new selective oxytocin receptor antagonist, atosiban, appear to be as effective as beta-sympathomimetic drugs on uterine contractions with fewer side-effects. Prostaglandin synthetase inhibitors such as indomethacin may prevent uterine contractions and can be used prior to the 32nd week of pregnancy. A single course of corticosteroid treatment in two doses of 12 mg betamethasone or 6 mg of dexamethasone is important for the prevention of respiratory distress between the 24th and 34th weeks of pregnancy. Multiple doses may be harmful and should be avoided. In these cases management should depend on gestation age (fetal maturity). Uterine contractions after 34 weeks' gestation are not an indication for tocolytic treatment.

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Folic acid supplementation

Neural tube defects represent one of a limited number of congenital conditions for which primary prevention strategies are available. Despite strong clinical evidence to support the preventive effect of supplementary folic acid given prior to conception and continued throughout the first 12 weeks of pregnancy, there is limited recent epidemiological data to support the effectiveness of national folic acid supplementation programs. Whether folic acid fortification of staple foods will provide a more effective means of achieving further reductions in the prevalence rates for this condition remains open to question. Recent advances associating folic acid supplementation, hyperhomocysteinaemia and neural tube defects provide a new insight into the possible pathological mechanism of this and possibly other related congenital conditions.