Effect of multiple micronutrient supplementation on pregnancy and infant outcomes: a systematic review

Supplementation with multiple micronutrients (MM) during pregnancy may result in improved pregnancy and infant outcomes. We conducted meta-analyses of randomised controlled trials that evaluated the effects of prenatal supplementation with MM (defined as containing at least five micronutrients and typically included iron or iron and folic acid). The outcomes of interest were low birthweight (<2500 g), birthweight, small-for-gestational age (SGA), gestational age, preterm birth (<37 weeks' gestation), stillbirth and neonatal death, maternal morbidity and mortality. We identified eligible studies through PubMed and EMBASE database searches. Meta-analyses were performed by pooling results for outcomes that were reported from more than one trial and sub-analyses were conducted to evaluate the effect of timing of intervention and amount of iron. We included published results from 16 trials in this review. Compared with control supplementation that was usually iron plus folic acid in most studies, MM supplementation resulted in a significant reduction in the incidence of low birthweight [pooled risk ratio (RR) 0.86; 95% confidence interval (CI) 0.81, 0.91] and SGA (pooled RR 0.83 [95% CI 0.73, 0.95]) and an increase in mean birthweight (weighted mean difference (WMD) 52.6 g [95% CI 43.2 g, 62.0 g]). There was no significant difference in the overall risk of preterm birth, stillbirth, and maternal or neonatal mortality, but we found an increased risk of neonatal death for the MM group compared with iron-folate in the subgroup of five trials that began the intervention after the first trimester (RR 1.38 [95% CI 1.05, 1.81]). None of the studies evaluated maternal morbidity. Compared with iron plus folic acid supplementation alone, prenatal maternal supplementation with MM resulted in a reduction in the incidence of low birthweight and SGA but increased risk of neonatal death in the subgroup of studies that began the intervention after the first trimester.     

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.     

Effect of n-3 long-chain polyunsaturated fatty acid intake during pregnancy on maternal, infant, and child health outcomes: a systematic review

Evidence from observational studies and randomised trials has suggested a potential association between intake of n-3 long-chain polyunsaturated fatty acids (LCPUFA) during pregnancy and certain pregnancy and birth outcomes. Marine foods (e.g. fatty sea fish, algae) and select freshwater fish contain pre-formed n-3 LCPUFA, which serve as precursors for bioactive molecules (e.g. prostaglandins) that influence a variety of biological processes. The main objective of this analysis was to summarise evidence of the effect of n-3 LCPUFA intake during pregnancy on select maternal and child health outcomes. Searches were performed in PubMed, EMBASE, and other electronic databases to identify trials where n-3 LCPUFA were provided to pregnant women for at least one trimester of pregnancy. Data were extracted into a standardised abstraction table and pooled analyses were conducted using RevMan software. Fifteen randomised controlled trials were eligible for inclusion in the meta-analysis, and 14 observational studies were included in the general review. n-3 LCPUFA supplementation during pregnancy resulted in a modest increase in birthweight (mean difference = 42.2 g; [95% CI 14.8, 69.7]) and no significant differences in birth length or head circumference. Women receiving n-3 LCPUFA had a 26% lower risk of early preterm delivery (<34 weeks) (RR = 0.74; [95% CI 0.58, 0.94]) and there was a suggestion of decreased risk of preterm delivery (RR = 0.91; [95% CI 0.82, 1.01]) and low birthweight (RR = 0.92; [95% CI 0.83, 1.02]). n-3 LCPUFA in pregnancy did not influence the occurrence of pre-eclampsia, high blood pressure, infant death, or stillbirth. Our review of observational studies revealed mixed findings, with several large studies reporting positive associations between fish intake and birthweight and several reporting no associations. In conclusion, n-3 LCPUFA supplementation during pregnancy resulted in a decreased risk of early preterm delivery and a modest increase in birthweight. More studies in low- and middle-income countries are needed to determine any effect of n-3 LCPUFA supplementation in resource-poor settings, where n-3 PUFA intake is likely low.     

Vitamin A and carotenoids during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis

Vitamin A (VA) deficiency during pregnancy is common in low-income countries and a growing number of intervention trials have examined the effects of supplementation during pregnancy on maternal, perinatal and infant health outcomes. We systematically reviewed the literature to identify trials isolating the effects of VA or carotenoid supplementation during pregnancy on maternal, fetal, neonatal and early infant health outcomes. Meta-analysis was used to pool effect estimates for outcomes with more than one comparable study. We used GRADE criteria to assess the quality of individual studies and the level of evidence available for each outcome. We identified 23 eligible trials of which 17 had suitable quality for inclusion in meta-analyses. VA or beta-carotene (βC) supplementation during pregnancy did not have a significant overall effect on birthweight indicators, preterm birth, stillbirth, miscarriage or fetal loss. Among HIV-positive women, supplementation was protective against low birthweight (<2.5 kg) [risk ratio (RR) = 0.79 [95% confidence interval (CI) 0.64, 0.99]], but no significant effects on preterm delivery or small-for-gestational age were observed. Pooled analysis of the results of three large randomised trials found no effects of VA supplementation on neonatal/infant mortality, or pregnancy-related maternal mortality (random-effects RR = 0.86 [0.60, 1.24]) although high heterogeneity was observed in the maternal mortality estimate (I(2) = 74%, P = 0.02). VA supplementation during pregnancy was found to improve haemoglobin levels and reduce anaemia risk (<11.0 g/dL) during pregnancy (random-effects RR = 0.81 [0.69, 0.94]), also with high heterogeneity (I(2) = 52%, P = 0.04). We found no effect of VA/βC supplementation on mother-to-child HIV transmission in pooled analysis, although some evidence suggests that it may increase transmission. There is little consistent evidence of benefit of maternal supplementation with VA or βC during pregnancy on maternal or infant mortality. While there may be beneficial effects for certain outcomes, there may also be potential for harm through increased HIV transmission in some populations.     

Secular trends in the epidemiology of pre-eclampsia throughout 40 years in Norway: prevalence, risk factors and perinatal survival

Pre-eclampsia is a leading complication of pregnancy, associated with maternal and neonatal morbidity. The present study describes the epidemiology of pre-eclampsia in Norway, with data from the Medical Birth Registry of Norway, covering 40 years. We aimed at describing time trends in prevalence, selected risk factors and perinatal mortality. We also analysed time trends in recurrence risk of total pre-eclampsia and pre-eclampsia with preterm delivery. A total of 2,416,501 women giving birth during 1967-2008 were included. Prevalence of pre-eclampsia increased from 1967 to 1999 and decreased thereafter, with an overall prevalence of 3%. Rates increased more over time among younger than older women, resulting in a significantly lower excess risk of pre-eclampsia associated with high maternal age in later years. For example, relative risk (RR) of pre-eclampsia among primiparae aged ≥35 relative to <25 years changed from 2.4 [95% confidence interval (CI) 2.1, 2.7] in 1967-1976 to 1.2 [95% CI 1.1, 1.3] in 1999-2008. For recurrence risk, subsequent pregnancies to a mother were linked, with the mother being the unit of analysis. Recurrence risk of pre-eclampsia was high, particularly recurrence of preterm pre-eclampsia, with overall RR close to 50 of a second pregnancy with pre-eclampsia and preterm birth compared with women without pre-eclampsia in first pregnancies. Finally, stillbirth associated with pre-eclampsia decreased more than neonatal mortality over time, and in the last 5 years only a moderate excess risk of stillbirth and neonatal death was observed.     

Maternal nutrition and birth outcomes: effect of balanced protein-energy supplementation

The nutritional status of a woman before and during pregnancy is important for a healthy pregnancy outcome. Maternal malnutrition is a key contributor to poor fetal growth, low birthweight (LBW) and short- and long-term infant morbidity and mortality. This review summarised the evidence on association of maternal nutrition with birth outcomes along with review of effects of balanced protein-energy supplementation during pregnancy. A literature search was conducted on PubMed, WHOLIS, PAHO and Cochrane library. Only intervention studies were considered for inclusion and data were combined by meta-analyses if available from more than one study. Sixteen intervention studies were included in the review. Pooled analysis showed a positive impact of balanced protein-energy supplementation on birthweight compared with control [mean difference 73 (g) [95% confidence interval (CI) 30, 117]]. This effect was more pronounced in undernourished women compared with adequately nourished women. Combined data from five studies showed a reduction of 32% in the risk of LBW in the intervention group compared with control [relative risk (RR) 0.68 [95% CI 0.51, 0.92]]. There was a reduction of 34% in the risk of small-for-gestational-age babies in the intervention compared with the control group [RR 0.66 [95% CI 0.49, 0.89]]. The risk of stillbirth was also reduced by 38% in the intervention group compared with control [RR 0.62 [95% CI 0.40, 0.98]]. In conclusion, balanced protein-energy supplementation is an effective intervention to reduce the prevalence of LBW and small-for-gestational-age births, especially in undernourished women.     

Risk factors in term children for visual impairment without a known prenatal or postnatal cause

Risk factors were studied for visual impairment in children without known pre- or postnatal cause, for a decrease of visual acuity. Children born at term 1979-98 and with a visual impairment were identified from the Swedish Register of Visually Impaired Children and data were linked with the Swedish Medical Birth Registry. Maternal characteristics such as maternal age, parity, maternal smoking habits in early pregnancy, maternal education, nationality, and subfertility were studied as well as maternal diagnoses such as pre-eclampsia, prolonged second stage of labour, abruptio placentae, and placenta praevia. Mode of delivery was analysed as well as birthweight, and birthweight in relation to gestational age. Abruptio placentae turned out to be the strongest risk factor (OR = 8.24 [95% CI 5.01, 13.51]). Smoking did not give a statistically significant increased risk. There is an increased risk with breech delivery (OR = 2.01 [95% CI 1.28, 3.17]). Pre-eclampsia was associated with an increased risk (OR = 2.22 [95% CI 1.46, 3.38]). There is also an increase in risk at low birthweight and small-for-gestational-age as well as birthweight > 4 kg and large-for-gestational-age. In this study we found that risk factors particularly worth noticing in term children with a presumed perinatal cause of visual impairment are abruptio placentae, pre-eclampsia, excessively low as well as excessively high birthweight, and breech delivery, a fact worth noticing in current discussion on risks, advantages or excessive exploitation of caesarean section.     

Routine iron/folate supplementation during pregnancy: effect on maternal anaemia and birth outcomes

Iron deficiency is the most common nutritional deficiency globally. Children and women of reproductive age are at a particular risk of iron deficiency. Anaemia during pregnancy is a specific risk factor for adverse maternal and perinatal outcomes. The objective of this review was to assess the impact of routine iron supplementation on maternal anaemia and perinatal outcomes. A literature search was conducted for published randomised and quasi-randomised trials on PubMed and the Cochrane Library. Only those studies were included in the review that assessed the preventive effect of iron supplementation during pregnancy. Data from selected studies were double abstracted in a standardised excel sheet. The studies were graded according to study design, limitations, intervention specifics and outcome effects. Meta-analyses were conducted where data were available from more than one study for an outcome. After screening 5209 titles, 30 studies were selected for inclusion in this review. Daily iron supplementation resulted in 69% reduction in incidence of anaemia at term in the intervention group compared with control [relative risk (RR) 0.31 [95% confidence interval (CI) 0.22, 0.44]] and 66% reduction in iron deficiency anaemia at term (RR 0.44 [95% CI 0.28, 0.68]; random model) compared with no intervention/placebo. The quality grade for these outcomes was that of 'moderate' level. Routine daily iron supplementation during pregnancy resulted in a significant reduction of 20% in incidence of low birthweight in the intervention group compared with control (RR 0.80 [95% CI 0.71, 0.90]). Preventive iron supplementation during pregnancy has a significant benefit in reducing incidence of anaemia in mothers and low birthweight in neonates.     

Vitamin D during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis

Vitamin D has well-defined classical functions related to calcium metabolism and bone health but also has non-classical effects that may influence other aspects of health. There has been considerable recent interest in the role of vitamin D on outcomes related to pregnancy and young child health but few efforts have been made to systematically consolidate this evidence to inform the research and policy agenda for low-income countries. A systematic review was undertaken to identify intervention and observational studies of vitamin D supplementation, intake or status (25-hydroxy-vitamin D) during pregnancy on perinatal and infant health outcomes. Data from trials and observational studies isolating the effect of vitamin D supplementation and intake were extracted and study quality was evaluated. Meta-analysis was used to pool effect estimates. We identified five randomised trials with outcomes of relevance to our review. All had small sample size and dosage amount, duration and frequency varied as did the ability to correct deficiency. Pooled analysis of trials using fixed-effects models suggested protective effects of supplementation on low birthweight (three trials, risk ratio (RR) = 0.40 [95% confidence interval (CI) 0.23, 0.71]) and non-significant but suggestive effects of daily supplementation on small-for-gestational age (two trials, RR = 0.67 [0.40, 1.11]). No effect on preterm delivery (<37 weeks) was evident (two trials, RR = 0.77 [0.35, 1.66]). Little evidence from trials exists to evaluate the effect of vitamin D supplementation during pregnancy on maternal, perinatal or infant health outcomes. Based on both trials and observational studies, we recommend that future research explore small-for-gestational age, preterm delivery, pre-eclampsia, and maternal and childhood infections, as outcomes of interest. Trials should focus on populations with a high prevalence of vitamin D deficiency, explore the relevance of timing of supplementation, and the dosage used in such trials should be sufficient to correct deficiency.     

A population-based cohort study of the relation between maternal birthweight and risk of gestational diabetes mellitus in four racial/ethnic groups

Intrauterine growth retardation and low birthweight have been associated with an increased risk of insulin resistance and type II diabetes later in life. We hypothesised that maternal low birthweight is associated with an increased risk of gestational diabetes mellitus (GDM). Study subjects comprised women giving birth in Washington State between 1987 and 1995. Information for 21,528 births to non-Hispanic white women, 6359 to African-American women, 7456 to Native American women and 6496 to Hispanic women was available for analysis. All information was derived from statewide computerised vital records and hospital discharge summaries of obstetric and neonatal admissions with linkage to birth certificates of mothers. Maternal birthweight was collected from subjects' birth certificates. Information from both the birth certificates and the obstetric and neonatal admissions database was used to determine whether subjects developed GDM. Poisson regression models were estimated to calculate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for GDM by categories of maternal birthweight. The cumulative incidence of GDM among non-Hispanic white, African-American, Native American and Hispanic women was 2.8, 2.6, 2.7 and 3.0% respectively. After adjusting for maternal age, parity, cigarette smoking, history of chronic hypertension and participation in the Medicaid programme, non-Hispanic white women with a birthweight < 2000 g were 1.7 times more likely to have had their pregnancy complicated by GDM (RR = 1.7; 95% CI 0.8, 3.3) than those with a birthweight 3000-3999 g. The corresponding adjusted RRs for African-American, Native American, and Hispanic women were 2.8 [95% CI 1.2, 6.1], 3.1 [95% CI 1.2, 8.2] and 2.4 [95% CI 0.9, 6.0] respectively. Among African-American women, those with a birthweight > or = 4000 g also experienced a twofold increased risk of GDM (RR = 2.1; 95% CI 1.0, 4.1). This association of high birthweight and increased GDM risk was not found among women in the other three racial/ethnic groups. These findings suggest that individuals with low birthweight constitute a group at increased risk for GDM.     

Antihelminthics in pregnancy and maternal, newborn and child health

Soil-transmitted helminths (STHs), primarily Ascaris, Trichuris and hookworm, inflict a substantial morbidity burden on poor populations living in tropical and subtropical regions. Chronic STH infections can cause intestinal blood loss and nutrient loss and/or malabsorption, which can result in or exacerbate iron deficiency, anaemia and other nutritional deficiencies. More than 1 billion people are infected with at least one STH, and at least 44 million pregnant women are infected with hookworm alone. Pregnant women are especially vulnerable to the harmful consequences of these parasitic infections due to increased nutritional demands during pregnancy. We aimed to determine the effect of antihelminthics in pregnancy on maternal, newborn and child health (MNCH) outcomes. A systematic review was conducted using online databases, and relevant articles were hand searched. We included four observational studies in the general review and four randomised controlled trials (RCTs) in the meta-analysis (total n = 3777 for the meta-analysis). Antihelminthics in pregnancy had no overall benefit on maternal anaemia [risk ratio (RR) = 0.93 [95% confidence interval (CI) 0.79, 1.10]], low birthweight (RR = 0.96 [95% CI 0.72, 1.29]) or perinatal mortality (RR = 0.98 [95% CI 0.58, 1.68]). The risk of very low birthweight was lower in the antihelminthics group (RR = 0.21 [95% CI 0.05, 0.83]); however, this estimate included data from only two trials (total n = 1936). In all four trials, antihelminthics in pregnancy significantly decreased the prevalence of STH infection. Three observational studies showed that antihelminthics in pregnancy improved maternal iron status, two studies reported beneficial effects on birthweight, and two studies found a beneficial effect on infant survival. Although few RCTs to date have failed to collectively demonstrate a clear beneficial impact of antihelminthics in pregnancy on maternal, newborn and child health outcomes, findings from observational studies suggest a potential benefit on maternal anaemia, birthweight and infant mortality. This meta-analysis was limited by a dearth of evidence from RCTs, and further trials examining the effect of antihelminthics starting in the second trimester of pregnancy in poor, STH-endemic regions with high rates of anaemia are needed.     

Maternal night blindness during pregnancy is associated with low birthweight, morbidity, and poor growth in South India

Maternal night blindness is common during pregnancy in many developing countries. Previous studies have demonstrated important consequences of maternal night blindness during pregnancy on the health of the mother and newborn infant. We compared birthweight, 6-mo infant mortality, morbidity, and growth among infants of women who did and did not report a history of night blindness from a community-based, randomized trial of newborn vitamin A supplementation in south India. Birthweight was measured within 72 h of delivery. Infants were followed until 6 mo of age for mortality and morbidity was assessed at household visits every 2 wk. Anthropometry was assessed at 6 mo of age. A total of 12,829 live-born infants were included, 680 of whom were infants of mothers with night blindness during the index pregnancy. Maternal night blindness was associated with an increased risk of low birthweight in a dose-dependent fashion based on birthweight cut-offs: <2500 g, adjusted relative risk (RR) = 1.13 (95% CI = 1.01, 1.26); <2000 g, adjusted RR = 1.70 (95% CI = 1.27, 2.26); <1500 g, adjusted RR = 3.38 (95% CI = 1.18, 6.33); with an increased risk of diarrhea (adjusted RR = 1.16, 95% CI = 1.03, 1.30), dysentery (adjusted RR = 1.25, 95% CI = 1.03, 1.53), acute respiratory illness (adjusted RR = 1.32, 95% CI = 1.21, 1.44), and poor growth at 6 mo; underweight (adjusted RR = 1.14, 95% CI = 1.02, 1.26), stunting (adjusted RR = 1.19, 95% CI = 1.05, 1.34). Maternal night blindness was not associated with 6-mo infant mortality or wasting at 6 mo. This study demonstrates that there are important consequences to the infant of maternal vitamin A deficiency during pregnancy.     

Randomized, double-blind, placebo-controlled trial of selenium supplements among HIV-infected pregnant women in Tanzania: effects on maternal and child outcomes

BACKGROUND: In observational studies, adequate selenium status has been associated with better pregnancy outcomes and slowed HIV disease progression. OBJECTIVE: We investigated the effects of daily selenium supplements on CD4 cell counts, viral load, pregnancy outcomes, and maternal and infant mortality among 913 HIV-infected pregnant women. DESIGN: In this randomized, double-blind, placebo-controlled trial, eligible women between 12 and 27 wk of gestation were given daily selenium (200 mug as selenomethionine) or placebo as supplements from recruitment until 6 mo after delivery. All women received prenatal iron, folic acid, and multivitamin supplements irrespective of experimental assignment. RESULTS: The selenium regimen had no significant effect on maternal CD4 cell counts or viral load. Selenium was marginally associated with a reduced risk of low birth weight [relative risk (RR) = 0.71; 95% CI: 0.49, 1.05; P = 0.09] and increased risk of fetal death (RR = 1.58; 95% CI = 0.95, 2.63; P = 0.08), but had no effect on risk of prematurity or small-for-gestational age birth. The regimen had no significant effect on maternal mortality (RR = 1.02; 95% CI = 0.51, 2.04; P = 0.96). There was no significant effect on neonatal or overall child mortality, but selenium reduced the risk of child mortality after 6 wk (RR = 0.43; 95% CI = 0.19, 0.99; P = 0.048). CONCLUSION: Among HIV-infected women from Dar es Salaam, Tanzania, selenium supplements given during and after pregnancy did not improve HIV disease progression or pregnancy outcomes, but may improve child survival. This trial was registered at clinicaltrials.gov as NCT00197561.     

Risks of hypertensive disorders in the second pregnancy

This study examined the incidence of and risk factors for recurrent and newly developed hypertensive disorders in the second pregnancy. We analysed data on 1641 women who had both the first and second pregnancies in the Collaborative Perinatal Project, a large prospective cohort study at 12 hospitals in the US. Nineteen per cent [95% CI 14%, 24%] of women who had gestational hypertension in the first pregnancy, 32% [95% CI 17%, 48%] of those with pre-eclampsia and 46% [95% CI 32%, 60%] of patients with gestational hypertension or pre-eclampsia superimposed on chronic hypertension, had recurrent hypertensive disorders in the second pregnancy. Risk factors for recurrence included history of chronic hypertension and thromboembolism, early onset of hypertension in the first pregnancy or persistent hypertension after 5 weeks postpartum and high baseline blood pressure in the second pregnancy. Women with a normotensive first pregnancy but a severe small-for-gestational-age birth had twice the risk of developing hypertension in the second pregnancy (RR = 2.1, 95% CI, 1.1, 4.0). In summary, hypertensive disorders have a 20--50% recurrence rate in the second pregnancy. The earlier the onset of hypertension in the first pregnancy, the higher the overall recurrence rate. Intrauterine growth restriction of the first birth is an independent risk factor for hypertension in the second pregnancy.     

Pregnancy outcomes among visually impaired women in Washington State, 1987–2014

BackgroundWomen with visual impairment may have reduced ability to access standard care resources, however, information on their pregnancy and neonatal outcomes is limited.ObjectiveTo assess risk of adverse pregnancy and neonatal outcomes among visually impaired women in Washington State from 1987 to 2014.MethodsWe conducted a retrospective cohort study using linked Washington State birth/fetal death hospital discharge records to compare outcomes among women with and without visual impairment noted at their delivery hospitalization. Pregnancy conditions and outcomes evaluated included gestational diabetes, pre-eclampsia, labor induction and cesarean delivery. Neonatal outcomes included preterm delivery and birth weight <2500 g. We assessed length of maternal and infant delivery hospitalization. We performed Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CIs) for each outcome, adjusting for year of delivery, maternal age, and parity.ResultsMost adverse pregnancy and neonatal outcomes were similar for visually impaired (N = 232) and comparison women (N = 2362). However, visually impaired women had increased risks of severe pre-eclampsia (RR 3.77, 95% CI 1.69–8.43), labor induction (RR 1.33, 95% CI 1.10–1.61) and preterm delivery (RR 1.60, 95% CI 1.06–2.42). They were also more likely to have delivery hospitalizations of 3 or more days following a vaginal (RR 1.86, 95% CI 1.41–2.47). Among cesarean deliveries, infants of visually impaired women had increased risk (RR 1.24, 95% CI 1.02–1.51) of hospitalization for 3 or more days postpartum.ConclusionOur findings may be useful for obstetric providers in counseling their visually impaired patients.     

The effects of maternal body mass index on pregnancy outcome

The increasing prevalence of obesity is presenting a critical challenge to healthcare services. We examined the effect of Body Mass Index in early pregnancy on adverse pregnancy outcome. We performed a population register-based cohort study using data from the North Western Perinatal survey (N = 99,403 babies born during 2004–2006), based at The University of Manchester, UK. The main outcome measures were Caesarean section delivery, preterm birth, neonatal death, stillbirth, Macrosomia, small for gestational age and large for gestational age. The risk of preterm birth was reduced by almost 10% in overweight (RR = 0.89, [95% CI: 0.83, 0.95]) and obese women (RR = 0.90, [95% CI: 0.84, 0.97]) and was increased in underweight women (RR = 1.33, [95% CI: 1.16, 1.53]). Overweight (RR = 1.17, [95% CI: 1.09, 1.25]), obese (RR = 1.35, [95% CI: 1.25, 1.45]) and morbidly obese (RR = 1.24, [95% CI: 1.02, 1.52]) women had an elevated risk of post-term birth compared to normal women. The risk of fetal macrosomia and operative delivery increased with BMI such that morbidly obese women were at greatest risk of both (RR of macrosomia = 4.78 [95% CI: 3.86, 5.92] and RR of Caesarean section = 1.66 [95% CI: 1.61, 1.71] and a RR of emergency Caesarean section = 1.59 [95% CI: 1.45, 1.75]). Excessive leanness and obesity are associated with different adverse pregnancy outcomes with major maternal and fetal complications. Overweight and obese women have a higher risk of macrosomia and Caesarean delivery and lower risk of preterm delivery. The mechanism underlying this association is unclear and is worthy of further investigation.     

Pregnancy outcomes in smokers who develop pre-eclampsia

Maternal smoking reduces the risk of pre-eclampsia, but has been reported to increase the risk of adverse outcomes related to the disease. We used data from the trial of Calcium for Pre-eclampsia Prevention (CPEP) to explore whether clinical manifestations of pre-eclampsia were altered by maternal smoking. CPEP was a randomised study of 4589 nulliparous women conducted in five US medical centres. Smoking history was obtained at study enrolment and women were monitored for the development of hypertension, proteinuria, and other medical complications. Among pre-eclamptic women (n=274), the risk of severe disease was not elevated in smokers (adjusted odds ratio 0.87 [95% confidence interval (CI) 0.30, 2.51]). Compared with non-smokers, gestational age (days, +/-SE) at onset of pre-eclampsia was not reduced in smokers (264.8 +/- 1.5, and 268.2 +/- 5.5, respectively, P=0.48). The smoking-attributable deficit in birthweight was not increased in pre-eclamptic women compared with normotensive women (97 g [95% CI -49, 244] and 185 g [95% CI 141, 229] respectively). In conclusion, among women who developed pre-eclampsia, smoking during pregnancy was not associated with disease severity. We found no evidence that pre-eclampsia and smoking act synergistically to restrict fetal growth.     

Maternal multiple micronutrient supplementation and pregnancy outcomes in developing countries: meta-analysis and meta-regression

Objective

To systematically review randomized controlled trials comparing the effect of supplementation with multiple micronutrients versus iron and folic acid on pregnancy outcomes in developing countries.

Methods

MEDLINE and EMBASE were searched. Outcomes of interest were birth weight, low birth weight, small size for gestational age, perinatal mortality and neonatal mortality. Pooled relative risks (RRs) were estimated by random effects models. Sources of heterogeneity were explored through subgroup meta-analyses and meta-regression.

Findings

Multiple micronutrient supplementation was more effective than iron and folic acid supplementation at reducing the risk of low birth weight (RR: 0.86, 95% confidence interval, CI: 0.79–0.93) and of small size for gestational age (RR: 0.85; 95% CI: 0.78–0.93). Micronutrient supplementation had no overall effect on perinatal mortality (RR: 1.05; 95% CI: 0.90–1.22), although substantial heterogeneity was evident (I² = 58%; P for heterogeneity = 0.008). Subgroup and meta-regression analyses suggested that micronutrient supplementation was associated with a lower risk of perinatal mortality in trials in which > 50% of mothers had formal education (RR: 0.93; 95% CI: 0.82–1.06) or in which supplementation was initiated after a mean of 20 weeks of gestation (RR: 0.88; 95% CI: 0.80–0.97).

Conclusion

Maternal education or gestational age at initiation of supplementation may have contributed to the observed heterogeneous effects on perinatal mortality. The safety, efficacy and effective delivery of maternal micronutrient supplementation require further research.     

Maternal ethnicity and pre-eclampsia in New York City, 1995-2003

Studies on ethnic differences in the risk of pre-eclampsia are limited. We linked birth records for 902,460 singleton births for the period 1995-2003 in New York City with hospital discharge data to evaluate the association between ethnicity and the risk of pre-eclampsia and compare risks between US-born and foreign-born women. Logistic regression models adjusted for maternal age, maternal education, parity, self-reported pre-pregnancy maternal weight, smoking during pregnancy and year of delivery were used to compare each ethnic group with non-Hispanic White women. The prevalence of pre-eclampsia in this study population was 3.2%. Among the major ethnic groups considered in our study, East Asian women had the lowest risk of pre-eclampsia (1.4%) and Mexican women had the highest risk (5.0%). Compared with non-Hispanic White women, there was a slightly decreased risk for East Asian women (adjusted OR = 0.8, [95% CI 0.7, 0.8]), similar risk for North African women (adjusted OR = 1.1, [95% CI 0.9, 1.3]), and increased risk for all other major ethnic groups (adjusted ORs: 1.3, 2.9), with the highest risk for Mexican women (adjusted OR = 2.9, [95% CI 2.7, 3.1]). No difference in risks was observed for US- vs. foreign-born women with the exception that foreign-born South-East Asian and Pacific Islanders had an increased risk of pre-eclampsia (adjusted OR = 1.8, [95% CI 1.0, 3.1]) relative to those born in the US. We concluded that there was ethnic heterogeneity in the development of pre-eclampsia among women in New York City and that Asian subgroups should be examined separately in future studies on ethnicity. Our results should contribute to screening for pre-eclampsia taking ethnic variation into account, and may help to suggest leads for the study of the aetiology of the condition.     

Epidemiology of intestinal malrotation,Hawaii, 1986-99

Malrotation of the intestines occurs as a result of failure of normal intestinal rotation and fixation during early pregnancy. This study examined the epidemiology of malrotation in Hawaii during 1986-99, using data from a population-based birth defects registry. There were 81 cases of malrotation, resulting in a rate of 2.86 per 10 000 live births and fetal deaths. The first-year mortality rate was 15.8%. Other major birth defects were reported for 93.8% of the cases. The malrotation rate during 1993-99 was significantly higher than the rate during 1986-92 (rate ratio [RR] 1.42, 95% confidence interval [CI] 1.04, 1.90). The malrotation rate was inversely proportional to maternal age (P = 0.028). Compared with whites, the malrotation rate was significantly higher among Far East Asians (RR 1.95, 95% CI 1.12, 3.17), Pacific Islanders (RR 2.41, 95% CI 1.63, 3.44) and Filipinos (RR 1.82, 95% CI 1.02, 3.01). Malrotation rates did not differ significantly by sex (RR 0.98, 95% CI 0.70, 1.34) or plurality (RR 1.86, 95% CI 0.38, 5.44) but were significantly higher among livebirths with birthweight < 3000 g (RR 3.90, 95% CI 2.83, 5.24). With no other population-based studies of malrotation found in the literature, this study adds to the knowledge of the epidemiology of malrotation.