Zinc supplementation for improving pregnancy and infant outcome

Early pregnancy exposure to metal mixture and birth outcomes - A prospective study in Project Viva

BACKGROUND

Prenatal exposure to metals has been individually associated with birth outcomes. However, little is known about the effect of metal mixture, particularly at low exposure levels.

OBJECTIVES

To estimate individual and joint effects of metal mixture components on birth outcomes.

METHODS

We used data from 1,391 mother-infant pairs in Project Viva (1999-2002). We measured 11 metals in maternal 1st trimester erythrocyte; abstracted birth weight from medical records; calculated gestational age from last menstrual period or ultrasound; and obtained birth length (n = 729) and head circumference (n = 791) from research measurements. We estimated individual and joint effects of metals using multivariable linear and Bayesian kernel machine regressions.

RESULTS

In both single metal and metal mixture analyses, exposure to higher concentrations of arsenic was associated with lower birth weight in males, zinc with higher head circumference in females, and manganese with higher birth length in sex-combined analysis. We also observed sex-specific metal interactions with birth outcomes. Arsenic and manganese showed a synergistic association with birth weight in males, in whom an interquartile range (IQR) increase in arsenic was associated with 25.3 g (95% CI: -79.9, 29.3), 47.9 g (95% CI: -98.0, 2.1), and 72.2 g (95% CI: -129.8, -14.7) lower birth weight when manganese concentrations were at 25th, 50th, and 75th percentiles, respectively. Lead and zinc showed an antagonistic association with head circumference in males, where an IQR increase in lead was associated with 0.18 cm (95% CI: -0.35, -0.02), 0.10 cm (95% CI: -0.25, 0.04), 0.03 cm (95% CI: -0.2, 0.14) smaller head circumference when zinc concentrations were at 25th, 50th, and 75th percentiles, respectively. Exposure to higher concentrations of arsenic was also associated with lower gestational age in males when concentrations of manganese and lead were higher.

DISCUSSION

Maternal erythrocyte concentrations of arsenic, manganese, lead, and zinc were individually and interactively associated with birth outcomes. The associations varied by infant sex and exposure level of other mixture components.

Effect of maternal zinc supplementation or zinc status on pregnancy complications and perinatal outcomes: An umbrella review of meta-analyses

Zinc is an essential trace element involved in different physiological functions. During pregnancy, it plays a crucial role in healthy embryogenesis. This umbrella review, therefore, aimed to summarize the existing literature of meta-analyses evaluating the effect of maternal zinc supplementation or zinc status on maternal and neonatal outcomes. Two databases, PubMed and Scopus, were selected to search the available literature without any temporal restriction. The literature search was performed during October 2020 and a total of 192 records were identified through the literature search. After screening the titles and applying the inclusion/exclusion criteria, finally, 15 articles were included in this umbrella review. This umbrella review showed that maternal zinc supplements reduce the risk of preterm birth. Although no substantial effect of zinc supplements was found for other feto-maternal outcomes. Also, we found a significant relationship between low maternal zinc status and risk of pregnancy complications. Zinc supplements reduce the risk of preterm birth. Long-term interventions and cohort studies are needed for future research directions. Further studies and a thorough investigation will help to decide the recommended zinc dose or intake during pregnancy.

Effect of maternal zinc deficiency on offspring health: The epigenetic impact

BACKGROUND

Zinc deficiency is associated with adverse effects on maternal health and pregnancy outcomes. These consequences have been reported over the years from zinc supplementation trials and observational studies whereby outcomes of maternal, foetal and infant health were measured. Owing to the importance of zinc in the functions of epigenetic enzymes, pre-clinical studies have shown that its deficiency could disrupt biological activities that involve epigenetic mechanisms in offspring. Thus, this review assessed the link between epigenetics and the effects of maternal zinc deficiency on the offspring's health in animal studies.

METHODS

Research articles were retrieved without date restriction from PubMed, Web of Science, ScienceDirect, and Google Scholar databases, as well as reference lists of relevant articles. The search terms used were "zinc deficiency", "maternal zinc deficiency", "epigenetics", and "offspring." Six studies met the eligibility criteria and were reviewed.

RESULTS

All the eligible studies reported maternal zinc deficiency and observed changes in epigenetic markers on the progeny during prenatal and postnatal stages of development. The main epigenetic markers reported were global and gene specific methylation and/ or acetylation. The epigenetic changes led to mortality, disruption in development, and risk of later life diseases.

CONCLUSION

Maternal zinc deficiency is associated with epigenetic modifications in offspring, which induce pathologies and increase the risk of later life diseases. More research and insight into the epigenetic mechanisms could spring up new approaches to combat the associated disease conditions.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy, such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although these associations have not yet been established. This is an update of a review first published in 1997 and subsequently updated in 2007, 2012 and 2015.

OBJECTIVES

1. To compare the effects on maternal, fetal, neonatal and infant outcomes in healthy pregnant women receiving zinc supplementation versus no zinc supplementation, or placebo. 2. To assess the above outcomes in a subgroup analysis reviewing studies performed in women who are, or are likely to be, zinc-deficient.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 July 2020), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation versus no zinc supplementation or placebo administration during pregnancy, earlier than 27 weeks' gestation. We excluded quasi-randomised controlled trials. We intended to include studies presented only as abstracts, if they provided enough information or, if necessary, by contacting authors to analyse them against our criteria; we did not find any such studies.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

For this update, we included 25 randomised controlled trials (RCTs) involving over 18,000 women and their babies. The overall risk of bias was low in half of the studies. The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence). Further, zinc supplementation may make little or no difference in reducing the risk of stillbirth (RR 1.22, 95% CI 0.80 to 1.88; 7 studies, 3295 participants; low-certainty evidence), or perinatal deaths (RR 1.10, 95% CI 0.81 to 1.51; 2 studies, 2489 participants; low-certainty evidence). It is unclear whether zinc supplementation reduces neonatal death, because the certainty of the evidence is very low. Finally, for other birth outcomes, zinc supplementation may make little or no difference to mean birthweight (MD 13.83, 95% CI -15.81 to 43.46; 22 studies, 7977 participants; low-certainty evidence), and probably makes little or no difference in reducing the risk of low birthweight (RR 0.94, 95% CI 0.79 to 1.13; 17 studies, 7399 participants; moderate-certainty evidence) and small-for-gestational age babies when compared to placebo or no zinc supplementation (RR 1.02, 95% CI 0.92 to 1.12; 9 studies, 5330 participants; moderate-certainty evidence). We did not conduct subgroup analyses, as very few studies used normal zinc populations.

AUTHORS' CONCLUSIONS

There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes. Future research to address ways of improving the overall nutritional status of pregnant women, particularly in low-income regions, and not looking at zinc in isolation, should be an urgent priority.

Guided imagery for treating hypertension in pregnancy

BACKGROUND

Hypertension (high blood pressure) in pregnancy carries a high risk of maternal morbidity and mortality. Although antihypertensive drugs are commonly used, they have adverse effects on mothers and fetuses. Guided imagery is a non-pharmacological technique that has the potential to lower blood pressure among pregnant women with hypertension. Guided imagery is a mind-body therapy that involves the visualisation of various mental images to facilitate relaxation and reduction in blood pressure.

OBJECTIVES

To determine the effect of guided imagery as a non-pharmacological treatment of hypertension in pregnancy and its influence on perinatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, and two trials registers (October 2018). We also searched relevant conference proceedings and journals, and scanned the reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). We would have included RCTs using a cluster-randomised design, but none were identified. We excluded quasi-RCTs and cross-over trials.We sought intervention studies of various guided imagery techniques performed during pregnancy in comparison with no intervention or other non-pharmacological treatments for hypertension (e.g. quiet rest, music therapy, aromatherapy, relaxation therapy, acupuncture, acupressure, massage, device-guided slow breathing, hypnosis, physical exercise, and yoga).

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the trials for inclusion, extracted data, and assessed risk of bias for the included studies. We checked extracted data for accuracy, and resolved differences in assessments by discussion. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included two small trials (involving a total of 99 pregnant women) that compared guided imagery with quiet rest. The trials were conducted in Canada and the USA. We assessed both trials as at high risk of performance bias, and low risk of attrition bias; one trial was at low risk for selection, detection, and reporting bias, while the other was at unclear risk for the same domains.We could not perform a meta-analysis because the two included studies reported different outcomes, and the frequency of the intervention was slightly different between the two studies. One study performed guided imagery for 15 minutes at least twice daily for four weeks, or until the baby was born (whichever came first). In the other study, the intervention included guided imagery, self-monitoring of blood pressure, and thermal biofeedback-assisted relaxation training for four total hours; the participants were instructed to practice the procedures twice daily and complete at least three relief relaxation breaks each day. The control groups were similar - one was quiet rest, and the other was quiet rest as bed rest.None of our primary outcomes were reported in the included trials: severe hypertension (either systolic blood pressure of 160 mmHg or higher, or diastolic blood pressure of 110 mmHg or higher); severe pre-eclampsia, or perinatal death (stillbirths plus deaths in the first week of life). Only one of the secondary outcomes was measured.Low-certainty evidence from one trial (69 women) suggests that guided imagery may make little or no difference in the use of antihypertensive drugs (risk ratio 1.27, 95% confidence interval 0.72 to 2.22).

AUTHORS' CONCLUSIONS

There is insufficient evidence to inform practice about the use of guided imagery for hypertension in pregnancy.The available evidence for this review topic is sparse, and the effect of guided imagery for treating hypertension during pregnancy (compared with quiet rest) remains unclear. There was low-certainty evidence that guided imagery made little or no difference to the use of antihypertensive drugs, downgraded because of imprecision.The two included trials did not report on any of the primary outcomes of this review. We did not identify any trials comparing guided imagery with no intervention, or with another non-pharmacological method for hypertension.Large and well-designed RCTs are needed to identify the effects of guided imagery on hypertension during pregnancy and on other relevant outcomes associated with short-term and long-term maternal and neonatal health. Trials could also consider utilisation and costs of health service.

Epidural therapy for the treatment of severe pre-eclampsia in non labouring women

BACKGROUND

Pre-eclampsia is a pregnancy-specific multi-organ disorder, which is characterised by hypertension and multisystem organ involvement and which has significant maternal and fetal morbidity and mortality. Failure of the placental vascular remodelling and reduced uteroplacental flow form the etiopathological basis of pre-eclampsia. There are several established therapies for pre-eclampsia including antihypertensives and anticonvulsants. Most of these therapies aim at controlling the blood pressure or preventing complications of elevated blood pressure, or both. Epidural therapy aims at blocking the vasomotor tone of the arteries, thereby increasing uteroplacental blood flow. This review was aimed at evaluating the available evidence about the possible benefits and risks of epidural therapy in the management of severe pre-eclampsia, to define the current evidence level of this therapy, and to determine what (if any) further evidence is required.

OBJECTIVES

To assess the effectiveness, safety and cost of the extended use of epidural therapy for treating severe pre-eclampsia in non-labouring women. This review aims to compare the use of extended epidural therapy with other methods, which include intravenous magnesium sulphate, anticonvulsants other than magnesium sulphate, with or without use of the antihypertensive drugs and adjuncts in the treatment of severe pre-eclampsia.This review only considered the use of epidural anaesthesia in the management of severe pre-eclampsia in the antepartum period and not as pain relief in labour.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (13 July 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing epidural therapy versus traditional therapy for pre-eclampsia in the form of antihypertensives, anticonvulsants, magnesium sulphate, low-dose dopamine, corticosteroids or a combination of these, were eligible for inclusion. Trials using a cluster design, and studies published in abstract form only are also eligible for inclusion in this review. Cross-over trials were not eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

The two review authors independently assessed trials for inclusion and trial quality. There were no relevant data available for extraction.

MAIN RESULTS

We included one small study (involving 24 women). The study was a single-centre randomised trial conducted in Mexico. This study compared a control group who received antihypertensive therapy, anticonvulsant therapy, plasma expanders, corticosteroids and dypyridamole with an intervention group that received epidural block instead of the antihypertensives, as well as all the other four drugs. Lumbar epidural block was given using 0.25% bupivacaine, 10 mg bolus and 5 mg each hour on continuous epidural infusion for six hours. This study was at low risk of bias in three domains but was assessed to be high risk of bias in two domains due to lack of allocation concealment and blinding of women and staff, and unclear for random sequence generation and outcome assessor blinding.The included study did not report on any of this review's important outcomes. Meta-analysis was not possible.For the mother, these were: maternal death (death during pregnancy or up to 42 days after the end of the pregnancy, or death more than 42 days after the end of the pregnancy); development of eclampsia or recurrence of seizures; stroke; any serious morbidity: defined as at least one of stroke, kidney failure, liver failure, HELLP syndrome (haemolysis, elevated liver enzymes and low platelets), disseminated intravascular coagulation, pulmonary oedema.For the baby, these were: death: stillbirths (death in utero at or after 20 weeks' gestation), perinatal deaths (stillbirths plus deaths in the first week of life), death before discharge from the hospital, neonatal deaths (death within the first 28 days after birth), deaths after the first 28 days; preterm birth (defined as the birth before 37 completed weeks' gestation); and side effects of the intervention. Reported outcomesThe included study only reported on a single secondary outcome of interest to this review: the Apgar score of the baby at birth and after five minutes and there was no clear difference between the intervention and control groups.The included study also reported a reduction in maternal diastolic arterial pressure. However, the change in maternal mean arterial pressure and systolic arterial pressure, which were the other reported outcomes of this trial, were not significantly different between the two groups.

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence from randomised controlled trials to evaluate the effectiveness, safety or cost of using epidural therapy for treating severe pre-eclampsia in non-labouring women.High-quality randomised controlled trials are needed to evaluate the use of epidural agents as therapy for treatment of severe pre-eclampsia. The rationale for the use of epidural is well-founded. However there is insufficient evidence from randomised controlled trials to show that the effect of epidural translates into improved maternal and fetal outcomes. Thus, there is a need for larger, well-designed studies to come to an evidence-based conclusion as to whether the lowering of vasomotor tone by epidural therapy results in better maternal and fetal outcomes and for how long that could be maintained. Another important question that needs to be answered is how long should extended epidural be used to ensure any potential clinical benefits and what could be the associated side effects and costs. Interactions with other modalities of treatment and women's satisfaction could represent other avenues of research.

Upregulation of Zinc Absorption Matches Increases in Physiologic Requirements for Zinc in Women Consuming High- or Moderate-Phytate Diets during Late Pregnancy and Early Lactation

Background: Estimated physiologic requirements (PRs) for zinc increase in late pregnancy and early lactation, but the effect on dietary zinc requirements is uncertain.Objective: The aim of this study was to determine changes in daily fractional absorbed zinc and total absorbed zinc (TAZ) from ad libitum diets of differing phytate contents in relation to physiologic zinc requirements during pregnancy and lactation.Methods: This was a prospective observational study of zinc absorption at 8 (phase 1) and 34 (phase 2) wk of gestation and 2 (phase 3) and 6 (phase 4) mo of lactation. Participants were indigenous Guatemalan women of childbearing age whose major food staple was maize and who had been randomly assigned in a larger study to either of 2 ad libitum feeding groups: low-phytate maize (LP; 1.6 mg/g; n = 14) or control maize (C; 7.1 mg/g; n = 8). Total dietary zinc (milligrams per day, TDZ) and phytate (milligrams per day) were determined from duplicate diets and fractional absorption (FAZ) by dual isotope ratio technique (TAZ = TDZ × FAZ). All variables were examined longitudinally and by group and compared with PRs. TAZ values at later phases were compared with phase 1. Measured TAZ was compared with predicted TAZ for nonpregnant, nonlactating (NPNL) women.Results: TAZ was greater in the LP group than in the C group at all phases. All variables increased from phase 1 to phases 2 and 3 and declined at phase 4. TAZ increased by 1.25 mg/d (P = 0.045) in the C group and by 0.81 mg/d (P = 0.058) in the LP group at phase 2. At phase 3, the increases were 2.66 mg/d (P = 0.002) in the C group and 2.28 mg/d (P = 0.0004) in the LP group, compared with a 1.37-mg/d increase in PR. Measured TAZ was greater than predicted values in phases 2-4.Conclusions: Upregulation of zinc absorption in late pregnancy and early lactation matches increases in PRs of pregnant and lactating women, regardless of dietary phytate, which has implications for dietary zinc requirements of pregnant and lactating women.

Decreased Nutrient Intake Is Associated With Premature Cervical Remodeling

OBJECTIVE

To examine the direct relationship between nutrient intake and cervical remodeling.

DESIGN

Longitudinal descriptive design.

SETTING

Maternal-fetal medicine clinic in a Midwestern urban city.

PARTICIPANTS

Forty-seven pregnant African American women.

METHODS

Participants completed the Block brief food frequency questionnaire at 19 to 24 weeks and 27 to 29 weeks gestation and had quantitative ultrasonic attenuation estimates at 19 to 21 weeks, 23 to 25 weeks, 27 to 29 weeks, 31 to 33 weeks, and 35 to 37 weeks gestation.

RESULTS

Trajectory mixture models identified two subpopulations within our sample: those at risk (n = 36) and at less risk (n = 11) for premature cervical remodeling. More participants in the less-risk group consumed the dietary reference intake for calcium, vitamin A, folate, vitamin E, zinc, and vitamin D than in the at-risk group. The percentage of participants in the less-risk group who consumed the recommended dietary reference intake for vitamin E was twice the percentage of women in the at-risk group (82% and 44%, respectively; p = .004). Mean intake of calcium was almost 1.3 times more (p = .05) and for zinc was 1.5 times more (p = .04) in the less-risk group than in the at-risk group.

CONCLUSION

Practitioners can inform women that certain nutrients, particularly zinc, calcium, and vitamin E, could be important to the health of the cervix and inhibit premature cervical remodeling, which in turn may help prevent preterm birth.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

OBJECTIVES

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information. The quality of the evidence was assessed using GRADE.

MAIN RESULTS

We included 21 randomised controlled trials (RCTs) reported in 54 papers involving over 17,000 women and their babies. One trial did not contribute data. Trials were generally at low risk of bias. Zinc supplementation resulted in a small reduction in preterm birth (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.97 in 16 RCTs; 16 trials of 7637 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 0.93, 95% CI 0.78 to 1.12; 14 trials of 5643 women). No clear differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not. The GRADE quality of the evidence was moderate for preterm birth, small-for-gestational age, and low birthweight, and low for stillbirth or neonatal death and birthweight.

AUTHORS' CONCLUSIONS

The evidence for a 14% relative reduction in preterm birth for zinc compared with placebo was primarily represented by trials involving women of low income and this has some relevance in areas of high perinatal mortality. There was no convincing evidence that zinc supplementation during pregnancy results in other useful and important benefits. Since the preterm association could well reflect poor nutrition, studies to address ways of improving the overall nutritional status of populations in impoverished areas, rather than focusing on micronutrient and or zinc supplementation in isolation, should be an urgent priority.

Zinc: The Metal of Life

The importance of zinc was 1st reported for Aspergillus niger. It took over 75 y to realize that zinc is also an essential trace element for rats, and an additional 30 y went by before it was recognized that this was also true for humans. The adult body contains about 2 to 3 g of zinc. Zinc is found in organs, tissues, bones, fluids, and cells. It is essential for many physiological functions and plays a significant role in a number of enzyme actions in the living systems. Bioinformatics estimates report that 10% of the human proteome contains zinc-binding sites. Based on its role in such a plethora of cellular components, zinc has diverse biological functions from enzymatic catalysis to playing a crucial role in cellular neuronal systems. Thus, based on the various published studies and reports, it is pertinent to state that zinc is one of the most important essential trace metals in human nutrition and lifestyle. Its deficiency may severely affect the homeostasis of a biological system. This review compiles the role of zinc in prophylaxis/therapeutics and provides current information about its effect on living beings.

Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years of age

BACKGROUND

Zinc deficiency is prevalent in low- and middle-income countries, and contributes to significant diarrhoea-, pneumonia-, and malaria-related morbidity and mortality among young children. Zinc deficiency also impairs growth.

OBJECTIVES

To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged six months to 12 years of age.

SEARCH METHODS

Between December 2012 and January 2013, we searched CENTRAL, MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, Embase, African Index Medicus, Conference Proceedings Citation Index, Dissertation Abstracts, Global Health, IndMED, LILACS, WHOLIS, metaRegister of Controlled Trials, and WHO ICTRP.

SELECTION CRITERIA

Randomised controlled trials of preventive zinc supplementation in children aged six months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalised children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions.

DATA COLLECTION AND ANALYSIS

Two authors screened studies, extracted data, and assessed risk of bias. We contacted trial authors for missing information.

MAIN RESULTS

We included 80 randomised controlled trials with 205,401 eligible participants. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes were affected by risk of bias. The risk ratio (RR) for all-cause mortality was compatible with a reduction and a small increased risk of death with zinc supplementation (RR 0.95, 95% confidence interval (CI) 0.86 to 1.05, 14 studies, high-quality evidence), and also for cause-specific mortality due to diarrhoea (RR 0.95, 95% CI 0.69 to 1.31, four studies, moderate-quality evidence), lower respiratory tract infection (LRTI) (RR 0.86, 95% CI 0.64 to 1.15, three studies, moderate-quality evidence), or malaria (RR 0.90, 95% CI 0.77 to 1.06, two studies, moderate-quality evidence).Supplementation reduced diarrhoea morbidity, including the incidence of all-cause diarrhoea (RR 0.87, 95% CI 0.85 to 0.89, 26 studies, moderate-quality evidence), but the results for LRTI and malaria were imprecise: LRTI (RR 1, 95% CI 0.94 to 1.07, 12 studies, moderate-quality evidence); malaria (RR 1.05, 95% 0.95 to 1.15, four studies, moderate-quality evidence).There was moderate-quality evidence of a very small improvement in height with supplementation (standardised mean difference (SMD) -0.09, 95% CI -0.13 to -0.06; 50 studies), but the size of this effect might not be clinically important. There was a medium to large positive effect on zinc status.Supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46, five studies, high-quality evidence). We found no clear evidence of benefit or harm of supplementation with regard to haemoglobin or iron status. Supplementation had a negative effect on copper status.

AUTHORS' CONCLUSIONS

In our opinion, the benefits of preventive zinc supplementation outweigh the harms in areas where the risk of zinc deficiency is relatively high. Further research should determine optimal intervention characteristics such as supplement dose.

Maternal dietary nutrient intake and risk of preterm delivery

OBJECTIVE

To examine maternal dietary intake and preterm delivery.

STUDY DESIGN

Data included 5738 deliveries from the National Birth Defects Prevention Study. Odds ratios (ORs) reflected risks of delivery at <32, 32-34, or 35-36 versus ≥ 37 weeks for maternal intake in the lowest or highest quartile of nutrient intake compared with the middle two.

RESULTS

Among deliveries < 32 weeks, many ORs were ≥ 1.5 or ≤ 0.7, but few confidence intervals excluded one. ORs were ≥ 1.5 for lowest quartiles of protein, thiamin, riboflavin, choline, vitamin A, α-carotene, β-carotene, vitamin E, iron, copper, and zinc and for highest quartiles of carbohydrate, glycemic index, and Mediterranean Diet Score. ORs were ≤ 0.7 for lowest quartiles of glycemic index and betaine and for highest quartiles of protein, alanine, methionine, vitamin B6, betaine, and calcium. Few ORs met these criteria for later preterm deliveries.

CONCLUSIONS

Results suggested an association of nutrient intake with earlier preterm deliveries.

Zinc supplementation for improving pregnancy and infant outcome

BACKGROUND

It has been suggested that low serum zinc levels may be associated with suboptimal outcomes of pregnancy such as prolonged labour, atonic postpartum haemorrhage, pregnancy-induced hypertension, preterm labour and post-term pregnancies, although many of these associations have not yet been established.

OBJECTIVES

To assess the effects of zinc supplementation in pregnancy on maternal, fetal, neonatal and infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2011) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised trials of zinc supplementation in pregnancy. We excluded quasi-randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Three review authors applied the study selection criteria, assessed trial quality and extracted data. When necessary, we contacted study authors for additional information.

MAIN RESULTS

We included 20 randomised controlled trials (RCTs) reported in 51 papers involving over 15,000 women and their babies. Trials were generally at low risk of bias. Zinc supplementation resulted in a small but significant reduction in preterm birth (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.76 to 0.97 in 16 RCTs; 16 trials of 7637 women). This was not accompanied by a similar reduction in numbers of babies with low birthweight (RR 0.93, 95% CI 0.78 to 1.12; 14 trials of 5643 women). No significant differences were seen between the zinc and no zinc groups for any of the other primary maternal or neonatal outcomes, except for induction of labour in a single trial. No differing patterns were evident in the subgroups of women with low versus normal zinc and nutrition levels or in women who complied with their treatment versus those who did not.

AUTHORS' CONCLUSIONS

The evidence for a 14% relative reduction in preterm birth for zinc compared with placebo was primarily represented by trials involving women of low income and this has some relevance in areas of high perinatal mortality. There was no convincing evidence that zinc supplementation during pregnancy results in other useful and important benefits. Since the preterm association could well reflect poor nutrition, studies to address ways of improving the overall nutritional status of populations in impoverished areas, rather than focusing on micronutrient and or zinc supplementation in isolation, should be an urgent priority.

Maternal zinc intakes and homeostatic adjustments during pregnancy and lactation

Zinc plays critical roles during embryogenesis, fetal growth, and milk secretion, which increase the zinc need for pregnancy and lactation. Increased needs can be met by increasing the dietary zinc intake, along with making homeostatic adjustments in zinc utilization. Potential homeostatic adjustments include changes in circulating zinc, increased zinc absorption, decreased zinc losses, and changes in whole body zinc kinetics. Although severe zinc deficiency during pregnancy has devastating effects, systematic reviews and meta-analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit. We hypothesize, therefore, that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and, therefore, mitigate immediate detrimental effects due to a low zinc intake. The specific questions addressed are the following: How is zinc utilization altered during pregnancy and lactation? Are those homeostatic adjustments influenced by maternal zinc status, dietary zinc, or zinc supplementation? These questions are addressed by critically reviewing results from published human studies on zinc homeostasis during pregnancy and lactation carried out in different populations worldwide.

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

Poor maternal zinc status has been associated with foetal loss, congenital malformations, intra-uterine growth retardation, reduced birth weight, prolonged labour and preterm or post-term deliveries. A meta-analysis completed in 2007 showed that maternal zinc supplementation resulted in a small but significant reduction in preterm birth. The purposes of this analysis are to update that previous review and expand the scope of assessment to include maternal, infant and child health outcomes. Electronic searches were carried out to identify peer-reviewed, randomised controlled trials where daily zinc supplementation was given for at least one trimester of pregnancy. The co-authors applied the study selection criteria, assessed trial quality and abstracted data. A total of 20 independent intervention trials involving more than 11,000 births were identified. The 20 trials took place across five continents between 1977 and 2008. Most studies assessed the zinc effect against a background of other micronutrient supplements, but five were placebo-controlled trials of zinc alone. The provided dose of supplemental zinc ranged from 5 to 50 mg/day. Only the risk of preterm birth reached statistical significance (summary relative risk 0.86 [95% confidence interval 0.75, 0.99]). There was no evidence that supplemental zinc affected any parameter of foetal growth (risk of low birth weight, birth weight, length at birth or head circumference at birth). Six of the 20 trials were graded as high quality. The evidence that maternal zinc supplementation lowers the risk of preterm birth was graded low; evidence for a positive effect on other foetal outcomes was graded as very low. The effect of zinc supplementation on preterm birth, if causal, might reflect a reduction in maternal infection, a primary cause of prematurity. While further study would be needed to explore this possibility in detail, the overall public health benefit of zinc supplementation in pregnancy appears limited.

Zinc biofortification of rice in China: a simulation of zinc intake with different dietary patterns

A cross-sectional survey of 2819 adults aged 20 years and above was undertaken in 2002 in Jiangsu Province. Zinc intake was assessed using a consecutive 3-day 24-h dietary recall method. Insufficient and excess intake was determined according to the Chinese Dietary Recommended Intakes. Four distinct dietary patterns were identified namely "traditional", "macho", "sweet tooth", and "healthy". Intake of zinc from biofortified rice was simulated at an intermediate zinc concentration (2.7 mg/100 g) and a high zinc concentration (3.8 mg/100 g) in rice. Average total zinc intake was 12.0 ± 3.7 mg/day, and insufficiency of zinc intake was present in 15.4%. Simulated zinc intake from biofortified rice with intermediate and high zinc concentration decreased the prevalence of low zinc intake to 6.5% and 4.4%, respectively. The effect was most pronounced in the "traditional" pattern, with only 0.7% of insufficiency of zinc intake remaining in the highest quartile of the pattern. Zinc intake was inversely associated with the "sweet tooth" pattern. Zinc biofortifed rice improves dietary zinc intake and lowers risk for insufficient zinc intake, especially for subjects with a more "traditional" food pattern, but less for subjects with a "sweet tooth" food pattern.

Zinc in well water and infant mortality in bangladesh: a report from gonoshasthaya kendra

Zinc supplementation reduces the duration, severity and recurrence of diarrhoea in young children. This study examines whether zinc, found naturally in drinking water, reduced infant deaths from diarrhoea in rural Bangladesh. Information was compiled for births over two calendar years with follow-up for deaths within one year of birth. The study included 29,744 live births and 934 deaths in some 600 villages under the care of Gonoshasthaya Kendra (GK), grouped into 15 health centre regions within 12 upazillas. Individual matching of death to birth data was not possible, but information on exposures through well water and on potential confounders was available for each upazilla. Average concentration of zinc in well water, reported by the British Geological Survey, was grouped into high (>0.07 mg/L), moderate (0.020–0.070 mg/L) and low (<0.020 mg/L) concentrations. Odds ratios (OR) were calculated for zinc by age and cause of death. Zinc concentration was unrelated to all-cause mortality but a decrease in deaths from diarrhoea (N = 50) was seen in areas with high zinc (OR = 0.30; 95% CI 0.13–0.69). No relation to diarrhoeal deaths was found with other well contaminants (arsenic, manganese) having accounted for zinc. Upazillas with a high proportion of women without education had higher rates of death from diarrhea, but the decrease in risk with high zinc remained (OR adjusted = 0.41; 95% CI 0.20–0.84). It is concluded that exposure to zinc through drinking water may reduce risk of diarrhoeal deaths.

Racial disparities in preterm birth: an overview of the potential role of nutrient deficiencies

OBJECTIVE

To give an overview of the literature for evidence of nutrient deficiencies as contributors to the disparity in preterm birth (PTB) between African-American and Caucasian women.

DESIGN

Structured literature survey.

METHODS

We searched MEDLINE to identify observational and experimental studies that evaluated the relation between nutrient intake and/or supplementation and PTB. For nutrients for which studies supported an association, we searched MEDLINE for studies of the prevalence of deficiency in the USA by race.

MAIN OUTCOME MEASURES

Summarized findings on nutrients for which there is both evidence of a role in PTB and variability in the prevalence of deficiency by race.

RESULTS

Nutrient deficiencies for which there are varying levels of evidence for an association with PTB and a greater burden among African-American compared with Caucasian women include deficiencies of iron, folic acid, zinc, vitamin D, calcium and magnesium, and imbalance of ω-3 and ω-6 polyunsaturated fatty acids. There are inadequate high-quality studies that investigate the role of nutrient deficiencies in PTB, their potential interaction with other risks, the proportion of excess risk for which they account, and whether supplementation can reduce the risk of, and racial disparities in, PTB in US populations.

CONCLUSION

Deficiencies of several nutrients have varying levels of evidence of association with PTB and are of greater burden among African-American compared with Caucasian women. Although further research is needed, strategies that improve the nutritional status of African-American women may be a means of addressing a portion of the racial disparity in PTB.

Quantifying the fall in mortality associated with interventions related to hypertensive diseases of pregnancy

BACKGROUND

In this paper we review the evidence of the effect of health interventions on mortality reduction from hypertensive diseases in pregnancy (HDP). We chose HDP because they represent a major cause of death in low income countries and evidence of effect on maternal mortality from randomised studies is available for some interventions.

METHODS

We used four approaches to review the evidence of the effect of interventions to prevent or treat HDP on mortality reduction from HDP. We first reviewed the Cochrane Library to identify systematic reviews and individual trials of the efficacy of single interventions for the prevention or treatment of HDP. We then searched the literature for articles quantifying the impact of maternal health interventions on the reduction of maternal mortality at the population level and describe the approaches used by various authors for interventions related to HDP. Third, we examined levels of HDP-specific mortality over time or between regions in an attempt to quantify the actual or potential reduction in mortality from HDP in these regions or over time. Lastly, we compared case fatality rates in women with HDP-related severe acute maternal morbidity with those reported historically in high income countries before any effective treatment was available.

RESULTS

The Cochrane review identified 5 effective interventions: routine calcium supplementation in pregnancy, antiplatelet agents during pregnancy in women at risk of pre-eclampsia, Magnesium sulphate (MgS04) for the treatment of eclampsia, MgS04 for the treatment of pre-eclampsia, and hypertensive drugs for the treatment of mild to moderate hypertension in pregnancy.We found 10 studies quantifying the effect of maternal health interventions on reducing maternal mortality from HDP, but the heterogeneity in the methods make it difficult to draw uniform conclusions for effectiveness of interventions at various levels of the health system. Most authors include a health systems dimension aimed at separating interventions that can be delivered at the primary or health centre level from those that require hospital treatment, but definitions are rarely provided and there is no consistency in the types of interventions that are deemed effective at the various levels.The low levels of HDP related mortality in rural China and Sri Lanka suggest that reductions of 85% or more are within reach, provided that most women give birth with a health professional who can refer them to higher levels of care when necessary. Results from studies of severe acute maternal morbidity in Indonesia and Bolivia also suggest that mortality in women with severe pre-eclampsia or eclampsia in hospital can be reduced by more than 84%, even when the women arrive late.

CONCLUSIONS

The increasing emphasis on the rating of the quality of evidence has led to greater reliance on evidence from randomised controlled trials to estimate the effect of interventions. Yet evidence from randomised studies is often not available, the effects observed on morbidity may not translate in to mortality, and the distinction between efficacy and effectiveness may be difficult to make. We suggest that more use should be made of observational evidence, particularly since such data represent the actual effectiveness of packages of interventions in various settings.

Magnesium sulphate versus diazepam for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, remains a rare but serious complication of pregnancy. A number of different anticonvulsants are used to control eclamptic fits and to prevent further fits.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with diazepam when used for the care of women with eclampsia. Magnesium sulphate is compared with phenytoin and with lytic cocktail in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2010) and CENTRAL (2010, Issue 3).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with diazepam for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two authors assessed and extracted data independently.

MAIN RESULTS

We have included seven trials, involving 1396 women. Three trials (1030 women) were good quality. Magnesium sulphate was associated with a reduction in maternal death (seven trials;1396 women; risk ratio (RR) 0.59, 95% confidence interval (CI) 0.38 to 0.92) and recurrence of seizures (seven trials;1390 women; RR 0.43, 95% CI 0.33 to 0.55) compared to diazepam. There were no clear differences in other measures of maternal morbidity.There was no clear difference in perinatal mortality (four trials; 788 infants; RR 1.04, 95% CI 0.81 to 1.34) or neonatal mortality (four trials; 759 infants; RR 1.18, 95% CI 0.75 to 1.84). In the magnesium sulphate group, fewer liveborn babies had an Apgar score less than seven at one minute (two trials; 597 babies; RR 0.75, 95% CI 0.65 to 0.87) or at five minutes (RR 0.70, 95% CI 0.54 to 0.90), and fewer appeared to need intubation at the place of birth (two trials; 591 infants; RR 0.67, 95% CI 0.45 to 1.00). There was no difference in admission to a special care nursery (four trials; 834 infants; RR 0.91, 95% CI 0.79 to 1.05), but fewer babies in the magnesium sulphate group had a length of stay more than seven days (three trials 631 babies; RR 0.66, 95% CI 0.46 to 0.96).

AUTHORS' CONCLUSIONS

Magnesium sulphate for women with eclampsia reduces the risk ratio of maternal death and of recurrence of seizures, compared with diazepam.

Perinatal interventions and survival in resource-poor settings: which work, which don't, which have the jury out?

Perinatal conditions make the largest contribution to the burden of disease in low-income countries. Although postneonatal mortality rates have declined, stillbirth and early neonatal mortality rates remain high in many countries in Africa and Asia, and there is a concentration of mortality around the time of birth. Our article begins by considering differences in the interpretation of 'intervention' to improve perinatal survival. We identify three types of

INTERVENTION

a single action, a collection of actions delivered in a package and a broader social or system approach. We use this classification to summarise the findings of recent systematic reviews and meta-analyses. After describing the growing evidence base for the effectiveness of community-based perinatal care, we discuss current concerns about integration: of women's and children's health programmes, of community-based and institutional care, and of formal and informal sector human resources. We end with some thoughts on the complexity of choices confronting women and their families in low-income countries, particularly in view of the growth in non-government and private sector healthcare.

Linkages among reproductive health, maternal health, and perinatal outcomes

Some interventions in women before and during pregnancy may reduce perinatal and neonatal deaths, and recent research has established linkages of reproductive health with maternal, perinatal, and early neonatal health outcomes. In this review, we attempted to analyze the impact of biological, clinical, and epidemiologic aspects of reproductive and maternal health interventions on perinatal and neonatal outcomes through an elucidation of a biological framework for linking reproductive, maternal and newborn health (RHMNH); care strategies and interventions for improved perinatal and neonatal health outcomes; public health implications of these linkages and implementation strategies; and evidence gaps for scaling up such strategies. Approximately 1000 studies (up to June 15, 2010) were reviewed that have addressed an impact of reproductive and maternal health interventions on perinatal and neonatal outcomes. These include systematic reviews, meta-analyses, and stand-alone experimental and observational studies. Evidences were also drawn from recent work undertaken by the Child Health Epidemiology Reference Group (CHERG), the interconnections between maternal and newborn health reviews identified by the Global Alliance for Prevention of Prematurity and Stillbirth (GAPPS), as well as relevant work by the Partnership for Maternal, Newborn and Child Health. Our review amply demonstrates that opportunities for assessing outcomes for both mothers and newborns have been poorly realized and documented. Most of the interventions reviewed will require more greater-quality evidence before solid programmatic recommendations can be made. However, on the basis of our review, birth spacing, prevention of indoor air pollution, prevention of intimate partner violence before and during pregnancy, antenatal care during pregnancy, Doppler ultrasound monitoring during pregnancy, insecticide-treated mosquito nets, birth and newborn care preparedness via community-based intervention packages, emergency obstetrical care, elective induction for postterm delivery, Cesarean delivery for breech presentation, and prophylactic corticosteroids in preterm labor reduce perinatal mortality; and early initiation of breastfeeding and birth and newborn care preparedness through community-based intervention packages reduce neonatal mortality. This review demonstrates that RHMNH are inextricably linked, and that, therefore, health policies and programs should link them together. Such potential integration of strategies would not only help improve outcomes for millions of mothers and newborns but would also save scant resources. This would also allow for greater efficiency in training, monitoring, and supervision of health care workers and would also help families and communities to access and use services easily.

Magnesium sulphate versus phenytoin for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, remains a rare but serious complication of pregnancy. A number of different anticonvulsants have been used to control eclamptic fits and to prevent further seizures.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with phenytoin when used for the care of women with eclampsia. Magnesium sulphate is compared with diazepam and with lytic cocktail in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2010).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with phenytoin for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data.

MAIN RESULTS

We have included data from seven trials, involving 972 women. One large trial (775 women) was of good quality. Magnesium sulphate was associated with a substantial reduction in the recurrence of seizures, when compared to phenytoin (six trials, 972 women; risk ratio (RR) 0.34, 95% confidence interval (CI) 0.24 to 0.49). The trend in maternal mortality favours magnesium sulphate, but the difference does not reach statistical significance (three trials, 847 women; RR 0.50, 95% CI 0.24 to 1.05). There were reductions in the risk of pneumonia (one trial, RR 0.44, 95% CI 0.24 to 0.79), ventilation (one trial, RR 0.68, 95% CI 0.50 to 0.91) and admission to an intensive care unit (one trial, RR 0.67, 95% CI 0.50 to 0.89) associated with the use of magnesium sulphate rather than phenytoin.For the baby, magnesium sulphate was associated with fewer admissions to a special care baby unit (SCBU) (one trial, 518 babies; RR 0.73, 95% CI 0.58 to 0.91) and fewer babies who died or were in SCBU for more than seven days (one trial, 643 babies; RR 0.77, 95% CI 0.63 to 0.95) than phenytoin. There was no clear difference in perinatal deaths (two trials, 665 babies; (RR 0.85, 95% CI 0.67 to 1.09).

AUTHORS' CONCLUSIONS

Magnesium sulphate, rather than phenytoin, for women with eclampsia reduces the risk ratio of recurrence of seizures, probably reduces the risk of maternal death, and improves outcome for the baby. Magnesium sulphate is the drug of choice for women with eclampsia. The use of phenytoin should be abandoned.

Micronutrients, birth weight, and survival

Maternal micronutrient requirements during pregnancy increase to meet the physiologic changes in gestation and fetal demands for growth and development. Maternal micronutrient deficiencies are high and coexist in many settings, likely influencing birth and newborn outcomes. The only recommendation for pregnancy currently exists for iron and folic acid use. Evidence is convincing that maternal iron supplementation will improve birth weight and perhaps gestational length. In one randomized trial, iron supplementation during pregnancy reduced child mortality in the offspring compared with the control group. Few other single micronutrients given antenatally, including vitamin A, zinc, and folic acid, have been systematically shown to confer such a benefit. A meta-analysis of 12 trials of multiple micronutrient supplementation compared with iron-folic acid reveals an overall 11% reduction in low birth weight but no effect on preterm birth and perinatal or neonatal survival. Currently, data are unconvincing for replacing supplementation of antenatal iron-folic acid with multiple micronutrients.

Magnesium sulphate versus lytic cocktail for eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure in association with pre-eclampsia, is a rare but serious complication of pregnancy. A number of different anticonvulsants have been used to control eclamptic fits and to prevent further seizures.

OBJECTIVES

The objective of this review was to assess the effects of magnesium sulphate compared with lytic cocktail (usually chlorpromazine, promethazine and pethidine) when used for the care of women with eclampsia. Magnesium sulphate is compared with diazepam and with phenytoin in other Cochrane reviews.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010) and the Cochrane Central Register of Trials (The Cochrane Library 2010, Issue 2).

SELECTION CRITERIA

Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with lytic cocktail for women with a clinical diagnosis of eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors (L Duley and D Chou) assessed trial quality and extracted data.

MAIN RESULTS

We included three small trials (total 397 women) of average quality in the review. Magnesium sulphate was associated with fewer maternal deaths (risk ratio (RR) 0.14, 95% confidence interval (CI) 0.03 to 0.59; 3 trials, 397 women) and was better at preventing further seizures (RR 0.06, 95% CI 0.03 to 0.12; 3 trials, 397 women) than lytic cocktail. Magnesium sulphate was also associated with less respiratory depression (RR 0.12, 95% CI 0.02 to 0.91; 2 trials, 198 women), less coma (RR 0.04, 95% CI 0.00 to 0.74; 1 trial, 108 women), and less pneumonia (RR 0.20, 95% CI 0.06 to 0.67; 2 trials, 307 women). There was no clear difference in the RR for any death of the baby (RR 0.35, 95% CI 0.05 to 2.38, random effects; 2 trials, 177 babies).

AUTHORS' CONCLUSIONS

Magnesium sulphate, rather than lytic cocktail, for women with eclampsia reduces the RR of maternal death, of further seizures and of serious maternal morbidity (respiratory depression, coma, pneumonia). Magnesium sulphate is the anticonvulsant of choice for women with eclampsia; the use of lytic cocktail should be abandoned.

Maternal gestational zinc supplementation does not influence multiple aspects of child development at 54 mo of age in Peru

BACKGROUND

Zinc is necessary for central nervous system development, and maternal zinc status has been associated with developmental differences in offspring.

OBJECTIVE

The objective was to evaluate differences in cognitive, social, and behavioral function in Peruvian children at 54 mo of age whose mothers participated during pregnancy in a zinc supplementation trial.

DESIGN

We attempted to follow up 205 children from a prenatal zinc supplementation trial and present data on 184 (90%) children-86 whose mothers took 25 mg zinc/d in addition to 60 mg iron and 250 microg folic acid and 98 whose mothers took iron and folic acid only. Following a standardized protocol, we assessed children's intelligence, language and number skills, representational ability, interpersonal understanding, and adaptive behavior and behavioral adjustment. We also assessed aspects of the mother (eg, age, education, verbal intelligence, stresses, and social support in parenting) and the home environment [HOME (Home Observation for the Measurement of the Environment) inventory].

RESULTS

No differences were observed between any of the tests used to characterize cognitive, social, or behavioral development (P > 0.05). Child sex, parity, or treatment compliance did not modify the effects of supplementation on any outcomes.

CONCLUSION

The addition of zinc to prenatal supplements did not influence developmental outcomes in Peruvian children when assessed at 4.5 y of age.

International perspective on early-onset neonatal sepsis

Infections are a major cause of neonatal death in developing countries. High-quality information on the burden of early-onset neonatal sepsis and sepsis-related deaths is limited in most of these settings. Simple preventive and treatment strategies have the potential to save many newborns from sepsis-related death. Implementation of public health programs targeting newborn health will assist attainment of Millennium Development Goals of reduction in child mortality.

Evidence for perinatal and child health care guidelines in crisis settings: can Cochrane help?

BACKGROUND

It is important that healthcare provided in crisis settings is based on the best available research evidence. We reviewed guidelines for child and perinatal health care in crisis situations to determine whether they were based on research evidence, whether Cochrane systematic reviews were available in the clinical areas addressed by these guidelines and whether summaries of these reviews were provided in Evidence Aid.

METHODS

Broad internet searches were undertaken to identify relevant guidelines. Guidelines were appraised using AGREE and the clinical areas that were relevant to perinatal or child health were extracted. We searched The Cochrane Database of Systematic Reviews to identify potentially relevant reviews. For each review we determined how many trials were included, and how many were conducted in resource-limited settings.

RESULTS

Six guidelines met selection criteria. None of the included guidelines were clearly based on research evidence. 198 Cochrane reviews were potentially relevant to the guidelines. These reviews predominantly addressed nutrient supplementation, breastfeeding, malaria, maternal hypertension, premature labour and prevention of HIV transmission. Most reviews included studies from developing settings. However for large portions of the guidelines, particularly health services delivery, there were no relevant reviews. Only 18 (9.1%) reviews have summaries in Evidence Aid.

CONCLUSIONS

We did not identify any evidence-based guidelines for perinatal and child health care in disaster settings. We found many Cochrane reviews that could contribute to the evidence-base supporting future guidelines. However there are important issues to be addressed in terms of the relevance of the available reviews and increasing the number of reviews addressing health care delivery.

The plausibility of maternal nutritional status being a contributing factor to the risk for fetal alcohol spectrum disorders: the potential influence of zinc status as an example

There is increasing evidence that human pregnancy outcome can be significantly compromised by suboptimal maternal nutritional status. Poor diet results in a maternal-fetal environment in which the teratogenicity of other insults such as alcohol might be amplified. As an example, there is evidence that zinc (Zn) can interact with maternal alcohol exposure to influence the risk for fetal alcohol spectrum disorders (FASD). Studies with experimental animals have shown that the teratogenicity of alcohol is increased under conditions of Zn deficiency, whereas its teratogenicity is lessened when animals are given Zn-supplemented diets or Zn injections before the alcohol exposure. Alcohol can precipitate an acute-phase response, resulting in a subsequent increase in maternal liver metallothionein, which can sequester Zn and lead to decreased Zn transfer to the fetus. Importantly, the teratogenicity of acute alcohol exposure is reduced in metallothionein knockout mice, which can have improved Zn transfer to the conceptus relative to wild-type mice. Consistent with the above, Zn status has been reported to be low in alcoholic women at delivery. Preliminary data from two basic science and clinical nutritional studies that are ongoing as part of the international Collaborative Initiative on Fetal Alcohol Spectrum Disorders support the potential role of Zn, among other nutritional factors, relative to risk for FASD. Importantly, the nutrient levels being examined in these studies are relevant to general clinical populations and represent suboptimal levels rather than severe deficiencies. These data suggest that moderate deficiencies in single nutrients can act as permissive factors for FASD, and that adequate nutritional status or intervention through supplementation may provide protection from some of the adverse effects of prenatal alcohol exposure.

Global report on preterm birth and stillbirth (3 of 7): evidence for effectiveness of interventions

INTRODUCTION

Interventions directed toward mothers before and during pregnancy and childbirth may help reduce preterm births and stillbirths. Survival of preterm newborns may also be improved with interventions given during these times or soon after birth. This comprehensive review assesses existing interventions for low- and middle-income countries (LMICs).

METHODS

Approximately 2,000 intervention studies were systematically evaluated through December 31, 2008. They addressed preterm birth or low birth weight; stillbirth or perinatal mortality; and management of preterm newborns. Out of 82 identified interventions, 49 were relevant to LMICs and had reasonable amounts of evidence, and therefore selected for in-depth reviews. Each was classified and assessed by the quality of available evidence and its potential to treat or prevent preterm birth and stillbirth. Impacts on other maternal, fetal, newborn or child health outcomes were also considered. Assessments were based on an adaptation of the Grades of Recommendation Assessment, Development and Evaluation criteria.

RESULTS

Most interventions require additional research to improve the quality of evidence. Others had little evidence of benefit and should be discontinued. The following are supported by moderate- to high-quality evidence and strongly recommended for LMICs: Two interventions prevent preterm births--smoking cessation and progesterone. Eight interventions prevent stillbirths--balanced protein energy supplementation, screening and treatment of syphilis, intermittant presumptive treatment for malaria during pregnancy, insecticide-treated mosquito nets, birth preparedness, emergency obstetric care, cesarean section for breech presentation, and elective induction for post-term delivery. Eleven interventions improve survival of preterm newborns--prophylactic steroids in preterm labor, antibiotics for PROM, vitamin K supplementation at delivery, case management of neonatal sepsis and pneumonia, delayed cord clamping, room air (vs. 100% oxygen) for resuscitation, hospital-based kangaroo mother care, early breastfeeding, thermal care, and surfactant therapy and application of continued distending pressure to the lungs for respiratory distress syndrome

CONCLUSION

The research paradigm for discovery science and intervention development must be balanced to address prevention as well as improve morbidity and mortality in all settings. This review also reveals significant gaps in current knowledge of interventions spanning the continuum of maternal and fetal outcomes, and the critical need to generate further high-quality evidence for promising interventions.

Global report on preterm birth and stillbirth (1 of 7): definitions, description of the burden and opportunities to improve data

INTRODUCTION

This is the first of seven articles from a preterm birth and stillbirth report. Presented here is an overview of the burden, an assessment of the quality of current estimates, review of trends, and recommendations to improve data.

PRETERM BIRTH

Few countries have reliable national preterm birth prevalence data. Globally, an estimated 13 million babies are born before 37 completed weeks of gestation annually. Rates are generally highest in low- and middle-income countries, and increasing in some middle- and high-income countries, particularly the Americas. Preterm birth is the leading direct cause of neonatal death (27%); more than one million preterm newborns die annually. Preterm birth is also the dominant risk factor for neonatal mortality, particularly for deaths due to infections. Long-term impairment is an increasing issue.

STILLBIRTH

Stillbirths are currently not included in Millennium Development Goal tracking and remain invisible in global policies. For international comparisons, stillbirths include late fetal deaths weighing more than 1000g or occurring after 28 weeks gestation. Only about 2% of all stillbirths are counted through vital registration and global estimates are based on household surveys or modelling. Two global estimation exercises reached a similar estimate of around three million annually; 99% occur in low- and middle-income countries. One million stillbirths occur during birth. Global stillbirth cause-of-death estimates are impeded by multiple, complex classification systems.

RECOMMENDATIONS TO IMPROVE DATA

(1) increase the capture and quality of pregnancy outcome data through household surveys, the main data source for countries with 75% of the global burden; (2) increase compliance with standard definitions of gestational age and stillbirth in routine data collection systems; (3) strengthen existing data collection mechanisms--especially vital registration and facility data--by instituting a standard death certificate for stillbirth and neonatal death linked to revised International Classification of Diseases coding; (4) validate a simple, standardized classification system for stillbirth cause-of-death; and (5) improve systems and tools to capture acute morbidity and long-term impairment outcomes following preterm birth.

CONCLUSION

Lack of adequate data hampers visibility, effective policies, and research. Immediate opportunities exist to improve data tracking and reduce the burden of preterm birth and stillbirth.

Role of nutrition in the risk of preeclampsia

Preeclampsia (PE) accounts for about one-quarter of the cases of maternal mortality and ranks second among the causes of pregnancy-associated maternal deaths in Canada and worldwide. The identification of an effective strategy to prevent PE is a priority and a challenge for research in obstetrics. Progress has been hampered by inadequate understanding of the underlying etiology of the disease. The role of maternal diet in the etiology of PE has recently received increased attention. The objective of this paper is to provide an overview of the literature concerning 1) the current understanding of the pathogenesis of PE, 2) the biological plausibility and potential mechanisms underlying the associations between maternal dietary exposures, nutrition, and the risk of PE, and 3) the epidemiological findings of maternal nutrient intake in relation to the risk of PE.

Contribution of fish to intakes of micronutrients important for fetal development: a dietary survey of pregnant women in the Republic of Seychelles

OBJECTIVES

To characterise the diets of pregnant women in the Republic of Seychelles and to determine the contribution of fish to intakes of nutrients important for fetal and neonatal development.

DESIGN

Observational, prospective study.

SETTING

Seychelles Child Development Centre, Mahé, Republic of Seychelles.

SUBJECTS AND METHODS

Pregnant women (n 300) were recruited at their first visit to an antenatal clinic. At 28 weeks' gestation subjects completed a 4 d diet diary (n 273) and intakes were analysed using dietary analysis software.

RESULTS

Mean (sd) energy intake was 9.0 (2.5) MJ/d and fat intakes were higher than UK recommendations for almost two-thirds of the cohort. Fish consumption was lower than in previous surveys, suggesting a move towards a more Westernised diet. Low intakes of a number of nutrients important during pregnancy for fetal development (Fe, Zn, Se and iodine) were observed. However, women who met the current recommendations for these nutrients consumed significantly more fish than those who did not (97 v. 73 g/d).

CONCLUSIONS

The present study highlights the importance of fish in the diet of pregnant Seychellois women for ensuring adequate intakes of micronutrients important in fetal development. Dietary patterns in Seychelles, however, are in a state of transition, with a move towards a Western-style diet as evidenced by higher fat and lower fish intakes. If these dietary trends continue and fish consumption declines further, micronutrient status may be compromised. These findings suggest caution in establishing public health policies that promote limitation of fish intake during pregnancy.

Preconceptional folate supplementation and the risk of spontaneous preterm birth: a cohort study

BACKGROUND

Low plasma folate concentrations in pregnancy are associated with preterm birth. Here we show an association between preconceptional folate supplementation and the risk of spontaneous preterm birth.

METHODS AND FINDINGS

In a cohort of 34,480 low-risk singleton pregnancies enrolled in a study of aneuploidy risk, preconceptional folate supplementation was prospectively recorded in the first trimester of pregnancy. Duration of pregnancy was estimated based on first trimester ultrasound examination. Natural length of pregnancy was defined as gestational age at delivery in pregnancies with no medical or obstetrical complications that may have constituted an indication for delivery. Spontaneous preterm birth was defined as duration of pregnancy between 20 and 37 wk without those complications. The association between preconceptional folate supplementation and the risk of spontaneous preterm birth was evaluated using survival analysis. Comparing to no supplementation, preconceptional folate supplementation for 1 y or longer was associated with a 70% decrease in the risk of spontaneous preterm delivery between 20 and 28 wk (41 [0.27%] versus 4 [0.04%] spontaneous preterm births, respectively; HR 0.22, 95% confidence interval [CI] 0.08-0.61, p = 0.004) and a 50% decrease in the risk of spontaneous preterm delivery between 28 and 32 wk (58 [0.38%] versus 12 [0.18%] preterm birth, respectively; HR 0.45, 95% CI 0.24-0.83, p = 0.010). Adjustment for maternal characteristics age, race, body mass index, education, marital status, smoking, parity, and history of prior preterm birth did not have a material effect on the association between folate supplementation for 1 y or longer and spontaneous preterm birth between 20 and 28, and 28 to 32 wk (adjusted HR 0.31, 95% CI 0.11-0.90, p = 0.031 and 0.53, 0.28-0.99, p = 0.046, respectively). Preconceptional folate supplementation was not significantly associated with the risk of spontaneous preterm birth beyond 32 wk. The association between shorter duration (<1 y) of preconceptional folate supplementation and the risk of spontaneous preterm birth was not significant after adjustment for maternal characteristics. However, the risk of spontaneous preterm birth decreased with the duration of preconceptional folate supplementation (test for trend of survivor functions, p = 0.01) and was the lowest in women who used folate supplementation for 1 y or longer. There was also no significant association with other complications of pregnancy studied after adjustment for maternal characteristics.

CONCLUSIONS

Preconceptional folate supplementation is associated with a 50%-70% reduction in the incidence of early spontaneous preterm birth. The risk of early spontaneous preterm birth is inversely proportional to the duration of preconceptional folate supplementation. Preconceptional folate supplementation was specifically related to early spontaneous preterm birth and not associated with other complications of pregnancy.

What works? Interventions for maternal and child undernutrition and survival

We reviewed interventions that affect maternal and child undernutrition and nutrition-related outcomes. These interventions included promotion of breastfeeding; strategies to promote complementary feeding, with or without provision of food supplements; micronutrient interventions; general supportive strategies to improve family and community nutrition; and reduction of disease burden (promotion of handwashing and strategies to reduce the burden of malaria in pregnancy). We showed that although strategies for breastfeeding promotion have a large effect on survival, their effect on stunting is small. In populations with sufficient food, education about complementary feeding increased height-for-age Z score by 0.25 (95% CI 0.01-0.49), whereas provision of food supplements (with or without education) in populations with insufficient food increased the height-for-age Z score by 0.41 (0.05-0.76). Management of severe acute malnutrition according to WHO guidelines reduced the case-fatality rate by 55% (risk ratio 0.45, 0.32-0.62), and recent studies suggest that newer commodities, such as ready-to-use therapeutic foods, can be used to manage severe acute malnutrition in community settings. Effective micronutrient interventions for pregnant women included supplementation with iron folate (which increased haemoglobin at term by 12 g/L, 2.93-21.07) and micronutrients (which reduced the risk of low birthweight at term by 16% (relative risk 0.84, 0.74-0.95). Recommended micronutrient interventions for children included strategies for supplementation of vitamin A (in the neonatal period and late infancy), preventive zinc supplements, iron supplements for children in areas where malaria is not endemic, and universal promotion of iodised salt. We used a cohort model to assess the potential effect of these interventions on mothers and children in the 36 countries that have 90% of children with stunted linear growth. The model showed that existing interventions that were designed to improve nutrition and prevent related disease could reduce stunting at 36 months by 36%; mortality between birth and 36 months by about 25%; and disability-adjusted life-years associated with stunting, severe wasting, intrauterine growth restriction, and micronutrient deficiencies by about 25%. To eliminate stunting in the longer term, these interventions should be supplemented by improvements in the underlying determinants of undernutrition, such as poverty, poor education, disease burden, and lack of women's empowerment.