Nutritional supplementation and the outcome of pregnancy. I. Birth weight

Evidence that highly canalized fetal traits are sensitive to intergenerational effects of maternal developmental nutrition

OBJECTIVES

Maternal experiences before pregnancy predict birth outcomes, a key indicator of health trajectories, but the timing and pathways for these effects are poorly understood. Here we test the hypothesis that maternal pre-adult growth patterns predict pregnancy glucose and offspring fetal growth in Cebu, Philippines.

METHODS

Using multiple regression and path analysis, gestational age-adjusted birthweight and variables reflecting infancy, childhood, and post-childhood/adolescent weight gain (conditional weights) were used to predict pregnancy HbA1c and offspring birth outcomes among participants in the Cebu Longitudinal Health and Nutrition Survey.

RESULTS

Maternal early/mid-childhood weight gain predicted birth weight, length, and head circumference in female offspring. Late-childhood/adolescent weight gain predicted birth length, birth weight, skinfold thickness, and head circumference in female offspring, and head circumference in male offspring. Pregnancy HbA1c did not mediate relationships between maternal growth and birth size parameters.

DISCUSSION

In Cebu, maternal growth patterns throughout infancy, childhood, and adolescence predict fetal growth via a pathway independent of circulating glucose, with stronger impacts on female than male offspring, consistent with a role of developmental nutrition on offspring fetal growth. Notably, the strength of relationships followed a pattern opposite to what occurs in response to acute pregnancy stress, with strongest effects on head circumference and birth length and weakest on skinfolds. We speculate that developmental sensitivities are reversed for stable, long-term nutritional cues that reflect average local environments. These findings are relevant to public health and life-history theory as further evidence of developmental influences on health and resource allocation across the life course.

Prenatal fortified balanced energy-protein supplementation and birth outcomes in rural Burkina Faso: A randomized controlled efficacy trial

BACKGROUND

Providing balanced energy-protein (BEP) supplements is a promising intervention to improve birth outcomes in low- and middle-income countries (LMICs); however, evidence is limited. We aimed to assess the efficacy of fortified BEP supplementation during pregnancy to improve birth outcomes, as compared to iron-folic acid (IFA) tablets, the standard of care.

METHODS AND FINDINGS

We conducted an individually randomized controlled efficacy trial (MIcronutriments pour la SAnté de la Mère et de l'Enfant [MISAME]-III) in 6 health center catchment areas in rural Burkina Faso. Pregnant women, aged 15 to 40 years with gestational age (GA) <21 completed weeks, were randomly assigned to receive either fortified BEP supplements and IFA (intervention) or IFA (control). Supplements were provided during home visits, and intake was supervised on a daily basis by trained village-based project workers. The primary outcome was prevalence of small-for-gestational age (SGA) and secondary outcomes included large-for-gestational age (LGA), low birth weight (LBW), preterm birth (PTB), gestational duration, birth weight, birth length, Rohrer's ponderal index, head circumference, thoracic circumference, arm circumference, fetal loss, and stillbirth. Statistical analyses followed the intention-to-treat (ITT) principle. From October 2019 to December 2020, 1,897 pregnant women were randomized (960 control and 937 intervention). The last child was born in August 2021, and birth anthropometry was analyzed from 1,708 pregnancies (872 control and 836 intervention). A total of 22 women were lost to follow-up in the control group and 27 women in the intervention group. BEP supplementation led to a mean 3.1 percentage points (pp) reduction in SGA with a 95% confidence interval (CI) of -7.39 to 1.16 (P = 0.151), indicating a wide range of plausible true treatment efficacy. Adjusting for prognostic factors of SGA, and conducting complete cases (1,659/1,708, 97%) and per-protocol analysis among women with an observed BEP adherence ≥75% (1,481/1,708, 87%), did not change the results. The intervention significantly improved the duration of gestation (+0.20 weeks, 95% CI 0.05 to 0.36, P = 0.010), birth weight (50.1 g, 8.11 to 92.0, P = 0.019), birth length (0.20 cm, 0.01 to 0.40, P = 0.044), thoracic circumference (0.20 cm, 0.04 to 0.37, P = 0.016), arm circumference (0.86 mm, 0.11 to 1.62, P = 0.025), and decreased LBW prevalence (-3.95 pp, -6.83 to -1.06, P = 0.007) as secondary outcomes measures. No differences in serious adverse events [SAEs; fetal loss (21 control and 26 intervention) and stillbirth (16 control and 17 intervention)] between the study groups were found. Key limitations are the nonblinded administration of supplements and the lack of information on other prognostic factors (e.g., infection, inflammation, stress, and physical activity) to determine to which extent these might have influenced the effect on nutrient availability and birth outcomes.

CONCLUSIONS

The MISAME-III trial did not provide evidence that fortified BEP supplementation is efficacious in reducing SGA prevalence. However, the intervention had a small positive effect on other birth outcomes. Additional maternal and biochemical outcomes need to be investigated to provide further evidence on the overall clinical relevance of BEP supplementation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03533712.

Understanding Sex Differences in Childhood Undernutrition: A Narrative Review

Complementing a recent systematic review and meta-analysis which showed that boys are more likely to be wasted, stunted, and underweight than girls, we conducted a narrative review to explore which early life mechanisms might underlie these sex differences. We addressed different themes, including maternal and newborn characteristics, immunology and endocrinology, evolutionary biology, care practices, and anthropometric indices to explore potential sources of sex differences in child undernutrition. Our review found that the evidence on why sex differences occur is limited but that a complex interaction of social, environmental, and genetic factors likely underlies these differences throughout the life cycle. Despite their bigger size at birth and during infancy, in conditions of food deprivation, boys experience more undernutrition from as early as the foetal period. Differences appear to be more pronounced in more severe presentations of undernutrition and in more socioeconomically deprived contexts. Boys are more vulnerable to infectious disease, and differing immune and endocrine systems appear to explain some of this disadvantage. Limited evidence also suggests that different sociological factors and care practices might exert influence and have the potential to exacerbate or reverse observed differences. Further research is needed to better understand sex differences in undernutrition and the implications of these for child outcomes and prevention and treatment programming.

Effects of nutritional interventions during pregnancy on birth, child health and development outcomes: A systematic review of evidence from low- and middle-income countries

Background

Optimal nutrition plays a crucial role in pregnancy. Poor maternal nutrition and maternal obesity has risk factors for serious fetal complications and neonatal outcomes, including intrauterine growth restriction, congenital abnormalities, stillbirth, low birth weight (LBW), preterm birth, fetal macrosomia, increased risk of neonatal infections, neonatal hypothermia, and neonatal death. The prevalence of maternal malnutrition is higher in low- and middle-income countries (LMICs) (10-19%) when compared with high-income countries, with variation by region and by country. Several behavioral interventions, including dietary control and exercise, have been found to reduce the risk of these adverse outcomes. However, none has reviewed dietary interventions to prevent maternal obesity in pregnant women.

Objectives

The review aims to assess the effectiveness of balanced energy protein (BEP) supplementation, food distribution programs (FDPs), and dietary interventions to prevent maternal obesity during pregnancy on birth, child health, and developmental outcomes.

Search Methods

We searched Cochrane Controlled Trials Register (CENTRAL), MEDLINE, Embase, CINAHL, and 12 other databases, and trials registers for ongoing studies up until April 2019. We also searched for gray literature from different sources and for citations on Google Scholar and Web of Sciences. We also checked the reference lists of included studies and relevant reviews and contacted the authors of studies for any ongoing and unpublished studies. The search was followed by title/abstract screening, full-text screening and data extraction.

Selection Criteria

We included randomized control trials, and quasi experimental trials to evaluate the impact of nutritional interventions (BEP, FDP, and dietary interventions to prevent maternal obesity) compared to control or standard of care, among healthy pregnant women of any age living in LMICs.

Data Collection and Analysis

Two review authors independently assessed and screened studies for eligibility, extracted data, and assessed quality of the studies included in the review. We conducted a meta-analysis of all reported primary and secondary outcomes. Subgroup analysis and GRADE assessment was performed for all reported primary outcomes.

Main Results

The review included 15 studies, of these, eight were on BEP supplementation, five on FDP, and two on interventions for obesity prevention. BEP supplementation may show a reduction in the rate of stillbirths by 61% (risk ratio [RR], 0.39; 95% CI, 0.19-0.80; three studies, n = 1913; low quality on GRADE), perinatal mortality by 50% (RR, 0.50; 95% CI, 0.30-0.84; one study, n = 1446; low quality on GRADE), LBW infants by 40% (RR, 0.60; 95% CI, 0.41-0.86; three studies, n = 1830; low quality of evidence on GRADE); small for gestational age (SGA) by 29% (RR, 0.71; 95% CI, 0.54-0.94; five studies, n = 1844) and increased birth weight by 107.28 g (mean difference [MD], 107.28 g; 95% CI, 68.51-146.04, eight studies, n = 2190). An increase of 107.28 g of birthweight is clinically significant in the countries where the intervention was provided. BEP supplementation had no effect on miscarriage, neonatal mortality, infant mortality, preterm birth, birth length, and head circumference. FDP may show improvement in mean birth weight by 46 g (MD, 46.00 g; 95% CI, 45.10-46.90, three studies, n = 5272), in birth length by 0.20 cm (MD, 0.20 cm; 95% CI, 0.20-0.20, three studies, n = 5272), and reduction in stunting by 18% (RR, 0.82; 95% CI, 0.71-0.94; two studies; n = 4166), and wasting by 13% (RR, 0.87; 95% CI, 0.78-0.97; two studies, n = 3883). There was no effect of FDP on miscarriage, maternal mortality, perinatal mortality, neonatal mortality, infant mortality, preterm birth, LBW, SGA, head circumference, and underweight babies. Studies on interventions for obesity prevention among pregnant women failed to report on the primary outcomes. The studies showed a 195.57 g reduction in mean birth weight (MD, -195.57 g, 95% CI, -349.46 to -41.68, two studies, n = 180), and had no effect on birth length, and macrosomia.

Authors' Conclusions

Our review highlights improvement in maternal, birth, and child outcomes through BEP supplementation and FDP during pregnancy. But, due to the small number of included studies and low quality of evidence, we are uncertain of the effect of BEP supplementation, FDP and dietary interventions for prevention of obesity on maternal, and child outcomes. Thus, further good quality research is recommended to assess the effect of these interventions on maternal, child and developmental outcomes.

Babies and Bandidos: Birth outcomes in pacified favelas of Rio de Janeiro

This paper explores police operations "pacifying" Rio de Janeiro's favelas to estimate if positive shocks of policing affect birth outcomes. Estimates show that pregnancies residing within official "pacification" borders had 0.07 standard deviation better birth outcomes than pregnancies on the same street but giving birth shortly before the police's arrival. Pacification effects concentrate in the third trimester of gestation and are followed by increases in the number of prenatal visits. No evidence of spillovers is found in areas immediately circumventing pacification borders. Hospital-level estimates indicate no impacts on the supply of health services, stress/anxiety among women, or abortions.

A life history approach to prenatal supplementation: Building a bridge from biological anthropology to public health and nutrition

While prenatal supplementation with protein, lipids, carbohydrates, and micronutrients has been used to improve infant outcomes in undernourished populations since the 1960s with inconsistent results, a flourishing body of literature within biological anthropology has used life history theory to explain why supplemental resources are often allocated to maternal survival and future reproduction and not to the current offspring. To date, however, public health and nutrition researchers have not adopted evolutionary perspectives in designing or analyzing prenatal supplementation studies. The result is a long series of supplementation trials with unpredictable and often disappointing outcomes for women and children, as well as serious lacunae in the understanding of long-term consequences of supplementation for women. The goal of this article is to open a tactical conversation about how to build a bridge between the evolutionary logic of biological anthropology and the evidentiary standards and methods of public health and nutrition with the aim of advancing knowledge about reproductive and metabolic physiology and improving women's health over the life course. The article reviews recent prenatal supplementation studies and proposes programmatic strategies by which biological anthropologists and public health and nutrition workers may collaborate to define different conditions of prenatal supplement resource allocation and to target more effective interventions.

A village-matched evaluation of providing a local supplemental food during pregnancy in rural Bangladesh: a preliminary study

BACKGROUND

Prenatal balanced protein energy supplementation consumed by undernourished women improves mid-upper arm circumference in early infancy. This study aimed to identify whether locally produced maternal food-based supplementation improved anthropometric measures at birth and early infancy.

METHODS

A village-matched evaluation, applying principles of a cluster randomised controlled trial, of a locally produced supplemental food to 87 undernourished pregnant women. 12 villages (intervention: n = 8; control: n = 4) in Pirganj sub-district, Rangpur District, northern Bangladesh. Daily supplements were provided.

RESULTS

Anthropometric data at birth were available for 77 mother-infant dyads and longer-term infant growth data for 75 infants. Mid-upper arm circumference (MUAC) was significantly larger in infants of mothers in the intervention group compared with the control group at 6 months (p < 0.05). The mean birth weight in babies of supplemented mothers (mean: 2·91 kg; SD: 0·19) was higher than in babies of mothers in the control group (mean: 2·72 kg; SD: 0·13), and these changes persisted until 6 months. Also, the proportion of low birth weight babies in the intervention group was much lower (event rate = 0.04) than in the control group (event rate = 0.16). However, none of these differences were statistically significant (p > 0·05; most likely due to small sample size). The intervention reduced the risk of wasting at 6 months by 63.38% (RRR = 0.6338), and of low birth weight by 88·58% (RRR = 0.8858), with NNT of 2.22 and 6.32, respectively. Only three pregnant women require this intervention in order to prevent wasting at 6 months in one child, and seven need the intervention to prevent low birth weight of one child.

CONCLUSIONS

Locally produced food-based balanced protein energy supplementation in undernourished pregnant women in northern Bangladesh resulted in larger MUAC in infants at 6 months. Further research, with larger sample sizes, is required to confirm the role of locally produced supplementation for undernourished pregnant women on weight and linear growth in newborns and infants.

TRIAL REGISTRATION

This research was registered with the ISRCTN registry (ISRCTN97447076). This project had human research ethical approval from the James Cook University (Australia) Ethics committee (H4498) and the Bangladesh Medical Research Council (BMRC/NREC/2010-2013/58).

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Intergenerational impact of maternal overnutrition and obesity throughout pregnancy in sheep on metabolic syndrome in grandsons and granddaughters

We previously reported that maternal overnutrition and obesity (MO) throughout pregnancy and lactation in sheep (MOF0) decreases term fetal pancreatic β-cell numbers and increases perirenal adiposity producing hyperphagia, increased adiposity and insulin resistance in adult female offspring (MOF1) fed ad libitum. Pregnant female MOF1 exhibited increased blood glucose from mid to late gestation vs control F1 (CTRF1) though both groups ate only to NRC recommendations. MOF1 ewes delivered female offspring (F2) who like their MOF1 mothers exhibited increased abdominal adiposity and absent neonatal leptin surge. In the current work, we determined if adult MOF2 exhibited metabolic syndrome components when fed ad libitum. After weaning, MOF2 males (n = 5), MOF2 females (n = 6), CTRF2 males (n = 5), and CTRF2 females (n = 6) were fed to NRC requirements until 19 mo followed by 12-wk ad libitum feeding. Body weight and % fat increased (P < 0.01) in all F2 during this feeding trial. MOF2 males were heavier (P < 0.01) than CTRF2 males and females, and MOF2 females throughout the trial. By wk 8, baseline blood glucose concentrations increased (P < 0.001) in MOF2 females, but not other groups, remaining elevated throughout the trial. Baseline insulin was similar through wk 6, increasing (P < 0.05) at wk 8 in MOF2 females only. MOF2 female insulin returned to CTRF2 female levels during wk 10 and 12. The progressive increase of plasma glucose on wk 8 in association with increased insulin in MOF2 females but not other groups demonstrated a diet-induced increase (P < 0.001) in MOF2 female insulin resistance. The subsequent decline in insulin during wk 10 and 12 despite elevated glucose in MOF2 females is consistent with a decrease in glucose-stimulated pancreatic β-cell function. These data indicate that ad libitum feeding exceeds the pancreatic secretory response predisposing MOF2 females to hyperglycemia. Furthermore, there was a sex difference where MOF2 males increased body mass and MOF2 females displayed insulin/glucose dysregulation.

How maternal malnutrition affects linear growth and development in the offspring

Maternal malnutrition is common in the developing world and has detrimental effects on both the mother and infant. Pre-pregnancy nutritional status and weight gain during pregnancy are positively related to fetal growth and development. Internationally, there is no agreement on the method of diagnosis or treatment of moderate or severe malnutrition during pregnancy. Establishing clear guidelines for diagnosis and treatment will be essential in elevating the problem. Possible anthropometric measurements used to detect and monitor maternal malnutrition include pre-pregnancy BMI, weight gain, and mid upper arm circumference. Food supplements have the potential to increase gestational weight gain and energy intake which are positively associated with fetal growth and development. Overall more studies are needed to conclude the impact of food/nutrient supplements on infant growth in undernourished pregnant women in developing countries. Currently, a study underway may provide much needed documentation of the benefits of treating malnutrition in pregnancy.

Antenatal dietary education and supplementation to increase energy and protein intake

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of education during pregnancy to increase energy and protein intake, or of actual energy and protein supplementation, on energy and protein intake, and the effect on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015), reference lists of retrieved studies and contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials of dietary education to increase energy and protein intake, or of actual energy and protein supplementation, during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and checked for accuracy. Extracted data were supplemented by additional information from the trialists we contacted.

MAIN RESULTS

We examined 149 reports corresponding to 65 trials. Of these trials, 17 were included, 46 were excluded, and two are ongoing. Overall, 17 trials involving 9030 women were included. For this update, we assessed methodological quality of the included trials using the standard Cochrane criteria (risk of bias) and the GRADE approach. The overall risk of bias was unclear. Nutritional education (five trials, 1090 women) Women given nutritional education had a lower relative risk of having a preterm birth (two trials, 449 women) (risk ratio (RR) 0.46, 95% CI 0.21 to 0.98, low-quality evidence), and low birthweight (one trial, 300 women) (RR 0.04, 95% CI 0.01 to 0.14). Head circumference at birth was increased in one trial (389 women) (mean difference (MD) 0.99 cm, 95% CI 0.43 to 1.55), while birthweight was significantly increased among undernourished women in two trials (320 women) (MD 489.76 g, 95% CI 427.93 to 551.59, low-quality evidence), but did not significantly increase for adequately nourished women (MD 15.00, 95% CI -76.30 to 106.30, one trial, 406 women). Protein intake increased significantly (three trials, 632 women) (protein intake: MD +6.99 g/day, 95% CI 3.02 to 10.97). No significant differences were observed on any other outcomes such as neonatal death (RR 1.28, 95% CI 0.35 to 4.72, one trial, 448 women, low-quality evidence), stillbirth (RR 0.37, 95% CI 0.07 to 1.90, one trial, 431 women, low-quality evidence), small-for-gestational age (RR 0.97, 95% CI 0.45 to 2.11, one trial, 404 women, low-quality evidence) and total gestational weight gain (MD -0.41, 95% CI -4.41 to 3.59, two trials, 233 women). There were no data on perinatal death. Balanced energy and protein supplementation (12 trials, 6705 women)Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.60, 95% CI 0.39 to 0.94, five trials, 3408 women, moderate-quality evidence), and the mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26, Tau² = 1744, I² = 44%, 11 trials, 5385 women, moderate-quality evidence). There was also a significant reduction in the risk of small-for-gestational age (RR 0.79, 95% CI 0.69 to 0.90, I² = 16%, seven trials, 4408 women, moderate-quality evidence). No significant effect was detected for preterm birth (RR 0.96, 95% CI 0.80 to 1.16, five trials, 3384 women, moderate-quality evidence) or neonatal death (RR 0.68, 95% CI 0.43 to 1.07, five trials, 3381 women, low-quality evidence). Weekly gestational weight gain was not significantly increased (MD 18.63, 95% CI -1.81 to 39.07, nine trials, 2391 women, very low quality evidence). There were no data reported on perinatal death and low birthweight. High-protein supplementation (one trial, 1051 women)High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41, moderate-quality evidence). There was no significant effect for stillbirth (RR 0.81, 95% CI 0.31 to 2.15, one trial, 529 women), neonatal death (RR 2.78, 95% CI 0.75 to 10.36, one trial, 529 women), preterm birth (RR 1.14, 95% CI 0.83 to 1.56, one trial, 505 women), birthweight (MD -73.00, 95% CI -171.26 to 25.26, one trial, 504 women) and weekly gestational weight gain (MD 4.50, 95% CI -33.55 to 42.55, one trial, 486 women, low-quality evidence). No data were reported on perinatal death. Isocaloric protein supplementation (two trials, 184 women)Isocaloric protein supplementation (two trials, 184 women) had no significant effect on birthweight (MD 108.25, 95% CI -220.89 to 437.40) and weekly gestational weight gain (MD 110.45, 95% CI -82.87 to 303.76, very low-quality evidence). No data reported on perinatal mortality, stillbirth, neonatal death, small-for-gestational age, and preterm birth.

AUTHORS' CONCLUSIONS

This review provides encouraging evidence that antenatal nutritional education with the aim of increasing energy and protein intake in the general obstetric population appears to be effective in reducing the risk of preterm birth, low birthweight, increasing head circumference at birth, increasing birthweight among undernourished women, and increasing protein intake. There was no evidence of benefit or adverse effect for any other outcome reported.Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small-for-gestational age. High-protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced-protein supplementation alone had no significant effects on perinatal outcomes.The results of this review should be interpreted with caution. The risk of bias was either unclear or high for at least one category examined in several of the included trials, and the quality of the evidence was low for several important outcomes. Also, as the anthropometric characteristics of the general obstetric population is changing, those developing interventions aimed at altering energy and protein intake should ensure that only those women likely to benefit are included. Large, well-designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.

The effect of balanced protein energy supplementation in undernourished pregnant women and child physical growth in low- and middle-income countries: a systematic review and meta-analysis

The beneficial effect of balanced protein energy supplementation during pregnancy on subsequent child growth is unclear and may depend upon the mother entering pregnancy adequately nourished or undernourished. Systematic reviews to-date have included studies from high-, middle- and low-income countries. However, the effect of balanced protein energy supplementation should not be generalised. This review assesses the effect of balanced protein energy supplementation in undernourished pregnant women from low- and middle-income countries on child growth. A systematic review of articles published in English (1970-2015) was conducted via MEDLINE, Scopus, the Cochrane Register and hand searching. Only peer-reviewed experimental studies analysing the effects of balanced protein energy supplementation in undernourished pregnant women from low- and middle-income countries with measures of physical growth as the primary outcome were included. Two reviewers independently assessed full-text articles against inclusion criteria. Validity of eligible studies was ascertained using the Quality Assessment Tool for Quantitative Studies (EPHPP QAT). In total, seven studies met the inclusion criteria. All studies reported on birthweight, five on birth length, three on birth head circumference, and one on longer-term growth. Standardised mean differences were calculated using a random-effects meta-analysis. Balanced protein energy supplementation significantly improved birthweight (seven randomised controlled trials, n = 2367; d = 0.20, 95% confidence interval, 0.03-0.38, P = 0.02). No significant benefit was observed on birth length or birth head circumference. Impact of intervention could not be determined for longer-term physical growth due to limited evidence. Additional research is required in low- and middle-income countries to identify impacts on longer-term infant growth.

Effects of dietary interventions on neonatal and infant outcomes: a systematic review and meta-analysis

BACKGROUND

Nutrition plays a fundamental role in fetal growth and birth outcomes.

OBJECTIVE

We synthesized effects of dietary interventions before or during pregnancy on neonatal and infant outcomes.

DESIGN

Randomized controlled trials that assessed the whole diet or dietary components and neonatal or infant outcomes were included. Two authors independently identified articles to be included and assessed the methodologic quality. A meta-analysis was conducted separately for each outcome by using a random-effects model. Results were reported by dietary intervention as follows: 1) counseling, 2) food and fortified food products, or 3) a combination (counseling plus food) intervention, and 4) collectively for all dietary interventions. Results were subanalyzed by the nutrient of interest, country income, and BMI.

RESULTS

Of 2326 abstracts screened, a total of 29 randomized controlled trials (31 publications) were included in this review. Food and fortified food products were effective in increasing birth weight [standardized mean difference (SMD): 0.27; 95% CI: 0.14, 0.40; P < 0.01] and reducing the incidence of low birth weight (SMD: -0.22; 95% CI: -0.37, -0.06; P < 0.01). All dietary interventions and those focused on macronutrient intake also increased birth weight (P < 0.01) and length (P < 0.05) and reduced the incidence of low birth weight (P < 0.01). Dietary interventions in low-income countries and underweight or nutritionally at-risk populations increased birth weight (P < 0.05) and reduced the incidence of low birth weight (P = 0.01). No effects were seen for the following other outcomes: placental weight, head circumference, macrosomia, Apgar score, small for gestational age, large for gestational age, and perinatal mortality.

CONCLUSION

Additional high-quality randomized controlled trials that test different dietary interventions are required to identify maternal diet intakes that optimize neonatal and infant outcomes.

Effects of dietary interventions on pregnancy outcomes: a systematic review and meta-analysis

Dietary intake during pregnancy influences maternal health. Poor dietary practices during pregnancy have been linked to maternal complications. The objective was to determine the effect of dietary intervention before or during pregnancy on pregnancy outcomes. A systematic review was conducted without date restrictions. Randomised controlled trials (RCTs) evaluating whole diet or dietary components and pregnancy outcomes were included. Two authors independently identified papers for inclusion and assessed methodological quality. Meta-analysis was conducted separately for each outcome using random effects models. Results were reported by type of dietary intervention: (1) counselling; (2) food and fortified food products; or (3) combination (counseling + food); and collectively for all dietary interventions. Results were further grouped by trimester when the intervention commenced, nutrient of interest, country income and body mass index. Of 2326 screened abstracts, a total of 28 RCTs were included in this review. Dietary counselling during pregnancy was effective in reducing systolic [standardised mean difference (SMD) -0.26, 95% confidence interval (CI) -0.45 to -0.07; P < 0.001] and diastolic blood pressure (SMD -0.57, 95% CI -0.75 to -0.38; P < 0.001). Macronutrient dietary interventions were effective in reducing the incidence of preterm delivery (SMD -0.19, 95% CI -0.34 to -0.04; P = 0.01). No effects were seen for other outcomes. Dietary interventions showed some small, but significant differences in pregnancy outcomes including a reduction in the incidence of preterm birth. Further high-quality RCTs, investigating micronutrient provision from food, and combination dietary intervention, are required to identify maternal diet intakes that optimise pregnancy outcomes.

Macronutrient and sociodemographic determinants of gestational weight gain among HIV-negative women in Tanzania

BACKGROUND

The effect of dietary macronutrient composition on the rate of gestational weight gain among women in sub-Saharan Africa is unclear.

OBJECTIVE

To examine the effect of macronutrient intake on the rate of gestational weight gain among HIV-negative women in Tanzania.

METHODS

The weights of 8,428 women were measured monthly from 12 weeks of gestation to term. Prenatal dietary intake was estimated as the cumulative average of multiple 24-hour dietary recalls. The association between energy intake and percentage of energy from carbohydrate, protein, and total fat and rate of weight gain (grams per month) was estimated from generalized estimating equation models. Macronutrient effects were adjusted for total energy using the nutrient density model and maternal age, maternal height, maternal mid-upper-arm circumference, parity, marital status, maternal occupation, maternal education, household wealth, season, and treatment regimen assignment. Body mass index (BMI) was considered as a confounder and a potential modifier of the effect of macronutrient intake on gestational weight gain.

RESULTS

A 6 g/month increase in rate of weight gain was associated with every 100-kcal increment in daily total energy intake (95% CI, 1 to 12; p = .03). Analyses substituting 5% of energy from fat by protein showed that weight gain would decrease by 72 g/month (95% CI, 6 to 140; p = .03); substituting 5% of energy from carbohydrate by protein decreased gain by 70 g/month (95% CI, 15 to 124; p = .01). Baseline BMI did not modify these associations.

CONCLUSIONS

Further research on the effects of macronutrient composition on gestational weight gain is needed to inform the design of supplementation programs for women in developing countries.

Effects of protein energy supplementation during pregnancy on fetal growth: a review of the literature focusing on contextual factors

Background

Maternal diet during pregnancy is one of the most important factors associated with adequate fetal growth. There are many complications associated with fetal growth restriction that lead to lifelong effects. The aim of this review was to describe the studies examining the effects of protein energy supplementation during pregnancy on fetal growth focusing on the contextual differences.

Methods

Relevant articles published between 2007 and 2012 were identified through systematic electronic searches of the PubMed, Science Direct, and EBSCO database and the examination of the bibliographies of retrieved articles. The search aimed to identify studies examining pregnant women receiving protein and/or energy during pregnancy and to assess fetal growth measures. Data of effectiveness and practical aspects of protein energy supplementation during pregnancy were extracted and compiled.

Results

Twenty studies (11 randomized controlled trials, 8 controlled before and after, and 1 prospective study) were included in this review. Positive outcomes in infants and women cannot be expected if the supplementation is not needed. Therefore, it is essential to correctly select women who will benefit from dietary intervention programs during pregnancy. However, there is currently no consensus on the most effective method of identifying these women. The content of protein in the supplements considering total diet is also an important determinant of fetal growth. Balanced protein energy supplementation (containing up to 20% of energy as protein) given to pregnant women with energy or protein deficit appears to improve fetal growth, increase birth weight (by 95–324 g) and height (by 4.6–6.1 mm), and decrease the percentage of low birth weight (by 6%). Supplements with excess protein (>20% of energy as protein) provided to women with a diet already containing adequate protein may conversely impair fetal growth. There is also no consensus on the best time to start supplementation.

Conclusions

Strong quality studies examining adequate criteria to screen women who would benefit from supplementation, time to start supplementation, and type of supplements are warranted.

Early prenatal food supplementation ameliorates the negative association of maternal stress with birth size in a randomised trial

Low birthweight increases the risk of infant mortality, morbidity and poor development. Maternal nutrition and stress influence birth size, but their combined effect is not known. We hypothesised that an early-invitation time to start a prenatal food supplementation programme could reduce the negative influence of prenatal maternal stress on birth size, and that effect would differ by infant sex. A cohort of 1041 pregnant women, who had delivered an infant, June 2003-March 2004, was sampled from among 3267 in the randomised controlled trial, Maternal Infant Nutritional Interventions Matlab, conducted in Matlab, Bangladesh. At 8 weeks gestation, women were randomly assigned an invitation to start food supplements (2.5 MJ d(-1) ; 6 days a week) either early (∼9 weeks gestation; early-invitation group) or at usual start time for the governmental programme (∼20 weeks gestation; usual-invitation group). Morning concentration of cortisol was measured from one saliva sample/woman at 28-32 weeks gestation to assess stress. Birth-size measurements for 90% of infants were collected within 4 days of birth. In a general linear model, there was an interaction between invitation time to start the food supplementation programme and cortisol with birthweight, length and head circumference of male infants, but not female infants. Among the usual-invitation group only, male infants whose mothers had higher prenatal cortisol weighed less than those whose mothers had lower prenatal cortisol. Prenatal food supplementation programmes that begin first trimester may support greater birth size of male infants despite high maternal stress where low birthweight is a public health concern.

Maternal Prenatal Nutrition and Health in Grandchildren and Subsequent Generations

This review focuses on how maternal prenatal nutritional states may affect the health of grandchildren and later generations. We first summarize the limited current data in human populations relating to the potential transmission of phenotypes across multiple generations that result from the nutritional experience of a pregnant woman. We then discuss findings from other species, especially mammals, that provide important clues as to whether, and if so how, such transmission could occur in humans. Finally, we consider how studies of human populations could be best designed to detect transmission across multiple generations. We argue that just as epidemiologists embraced a life-course perspective to human health and disease in the twentieth century, we must now seek to better understand how health and disease could be shaped across multiple generations.

Antenatal dietary advice and supplementation to increase energy and protein intake

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of advice during pregnancy to increase energy and protein intake, or of actual energy and protein supplementation, on energy and protein intakes, and the effect on maternal and infant health outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (22 July 2011) and contacted researchers in the field. We updated the search on 12 July 2012 and added the results to the awaiting classification section of the review.

SELECTION CRITERIA

Randomised controlled trials of dietary advice to increase energy and protein intake, or of actual energy and protein supplementation, during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed risk of bias. Two review authors independently extracted data and checked for accuracy. Extracted data were supplemented by additional information from the trialists we contacted.

MAIN RESULTS

We examined 110 reports corresponding to 46 trials. Of these trials, 15 were included, 30 were excluded, and one is ongoing. Overall, 15 trials involving 7410 women were included.Nutritional advice (four trials, 790 women)Women given nutritional advice had a lower relative risk of having a preterm birth (two trials, 449 women) (risk ratio (RR) 0.46, 95% CI 0.21 to 0.98 ), head circumference at birth was increased in one trial (389 women) (mean difference (MD) 0.99 cm, 95% CI 0.43 to 1.55) and protein intake increased (three trials, 632 women) (protein intake: MD +6.99 g/day, 95% CI 3.02 to 10.97). No significant differences were observed on any other outcomes.Balanced energy and protein supplementation (11 trials, 5385 women)Risk of stillbirth was significantly reduced for women given balanced energy and protein supplementation (RR 0.62, 95% CI 0.40 to 0.98, five trials, 3408 women), mean birthweight was significantly increased (random-effects MD +40.96 g, 95% CI 4.66 to 77.26 , Tau(2)= 1744, I(2) = 44%, 11 trials, 5385 women). There was also a significant reduction in the risk of small-for-gestational age (RR 0.79, 95% CI 0.69 to 0.90, I(2) = 16%, seven trials, 4408 women). No significant effect was detected for preterm birth or neonatal death.High-protein supplementation (one trial, 1051 women)High-protein supplementation (one trial, 505 women), was associated with a significantly increased risk of small-for-gestational age babies (RR 1.58, 95% CI 1.03 to 2.41).Isocaloric protein supplementation (two trials, 184 women)Isocaloric protein supplementation (two trials,184 women) had no significant effect on birthweight and weekly gestational weight gain.

AUTHORS' CONCLUSIONS

This review provides encouraging evidence that antenatal nutritional advice with the aim of increasing energy and protein intake in the general obstetric population appears to be effective in reducing the risk of preterm birth, increasing head circumference at birth and increasing protein intake, there was no evidence of benefit or adverse effect for any other outcome reported.Balanced energy and protein supplementation seems to improve fetal growth, and may reduce the risk of stillbirth and infants born small-for-gestational age. High-protein supplementation does not seem to be beneficial and may be harmful to the fetus. Balanced-protein supplementation alone had no significant effects on perinatal outcomes.The results of this review should be interpreted with caution, the risk of bias was either unclear or high for at least one category examined in several of the included trials and the quality of the evidence was low for several important outcomes. Also the anthropometric characteristics of the general obstetric population is changing, therefore, those developing interventions aimed at altering energy and protein intake should ensure that only those women likely to benefit are included. Large, well designed randomised trials are needed to assess the effects of increasing energy and protein intake during pregnancy in women whose intake is below recommended levels.

Review of fortified food and beverage products for pregnant and lactating women and their impact on nutritional status

Fortified beverages and supplementary foods, when given during pregnancy, have been shown to have positive effects on preventing maternal anaemia and iron deficiency. Studies show that use of micronutrient fortified supplementary foods, especially those containing milk and/or essential fatty acids during pregnancy, increase mean birthweight by around 60-73 g. A few studies have also shown that fortified supplementary foods have impacts on increasing birth length and reducing preterm delivery. Fortification levels have ranged generally from 50% to 100% of the recommended nutrient intake (RNI). Iron, zinc, copper, iodine, selenium, vitamins A, D, E, C, B1, B2, B6, and B12, folic acid, niacin and pantothenic acid are important nutrients that have been included in fortified beverages and supplemental foods for pregnant and lactating women. While calcium has been shown to reduce the risk of pre-eclampsia and maternal mortality, calcium, phosphorus, potassium, magnesium and manganese can have negative impacts on organoleptic properties, so many products tested have not included these nutrients or have done so in a limited way. Fortified food supplements containing milk and essential fatty acids offer benefits to improving maternal status and pregnancy outcome. Fortified beverages containing only multiple micronutrients have been shown to reduce micronutrient deficiencies such as anaemia and iron deficiency.

Sex differences in fetal growth responses to maternal height and weight

Sex differences in fetal growth have been reported, but how this happens remains to be described. It is unknown if fetal growth rates, a reflection of genetic and environmental factors, express sexually dimorphic sensitivity to the mother herself. This analysis investigated homogeneity of male and female growth responses to maternal height and weight. The study sample included 3,495 uncomplicated singleton pregnancies followed longitudinally. Analytic models regressed fetal and neonatal weight on tertiles of maternal height and weight, and modification by sex was investigated (n = 1,814 males, n = 1,681 females) with birth gestational age, maternal parity, and smoking as covariates. Sex modified the effects of maternal height and weight on fetal growth rates and birth weight. Among boys, tallest maternal height influenced fetal weight growth before 18 gestational weeks of age (P = 0.006), and prepregnancy maternal weight and body mass index subsequently had influence (P < 0.001); this was not found among girls. Additionally, interaction terms between sex, maternal height, and maternal weight identified that males were more sensitive to maternal weight among shorter mothers (P = 0.003) and more responsive to maternal height among lighter mothers (P < or = 0.03), compared to females. Likewise, neonatal birth weight dimorphism varied by maternal phenotype. A male advantage of 60 g occurred among neonates of the shortest and lightest mothers (P = 0.08), compared to 150 and 191 g among short and heavy mothers, and tall and light-weight mothers, respectively (P = 0.01). Sex differences in response to maternal size are under-appreciated sources of variation in fetal growth studies and may reflect differential growth strategies.

Nutritional indicators of adverse pregnancy outcomes and mother-to-child transmission of HIV among HIV-infected women

BACKGROUND

Poor nutrition may be associated with mother-to-child transmission (MTCT) of HIV and other adverse pregnancy outcomes.

OBJECTIVE

The objective was to examine the relation of nutritional indicators with adverse pregnancy outcomes among HIV-infected women in Tanzania, Zambia, and Malawi.

DESIGN

Body mass index (BMI; in kg/m(2)) and hemoglobin concentrations at enrollment and weight change during pregnancy were prospectively related to fetal loss, neonatal death, low birth weight, preterm birth, and MTCT of HIV.

RESULTS

In a multivariate analysis, having a BMI < 21.8 was significantly associated with preterm birth [odds ratio (OR): 1.82; 95% CI: 1.34, 2.46] and low birth weight (OR: 2.09; 95% CI: 1.41, 3.08). A U-shaped relation between weight change during pregnancy and preterm birth was observed. Severe anemia was significantly associated with fetal loss or stillbirth (OR: 3.67; 95% CI: 1.16, 11.66), preterm birth (OR: 2.08; 95% CI: 1.39, 3.10), low birth weight (OR: 1.76; 95% CI: 1.07, 2.90), and MTCT of HIV by the time of birth (OR: 2.26; 95% CI: 1.18, 4.34) and by 4-6 wk among those negative at birth (OR: 2.33; 95% CI: 1.15, 4.73).

CONCLUSIONS

Anemia, poor weight gain during pregnancy, and low BMI in HIV-infected pregnant women are associated with increased risks of adverse infant outcomes and MTCT of HIV. Interventions that reduce the risk of wasting or anemia during pregnancy should be evaluated to determine their possible effect on the incidence of adverse pregnancy outcomes and MTCT of HIV.

Fetal origins of developmental plasticity: are fetal cues reliable predictors of future nutritional environments?

Evidence that fetal nutrition triggers permanent adjustments in a wide range of systems and health outcomes is stimulating interest in the evolutionary significance of these responses. This review evaluates the postnatal adaptive significance of fetal developmental plasticity from the perspective of life history theory and evolutionary models of energy partitioning. Birthweight is positively related to multiple metabolically costly postnatal functions, suggesting that the fetus has the capacity to distribute the burden of energy insufficiency when faced with a nutritionally challenging environment. Lowering total requirements may reduce the risk of negative energy balance, which disproportionately impacts functions that are not essential for survival but that are crucial for reproductive success. The long-term benefit of these metabolic adjustments is contingent upon the fetus having access to a cue that is predictive of its future nutritional environment, a problem complicated in a long-lived species by short-term ecologic fluctuations like seasonality. Evidence is reviewed suggesting that the flow of nutrients reaching the fetus provides an integrated signal of nutrition as experienced by recent matrilineal ancestors, which effectively limits the responsiveness to short-term ecologic fluctuations during any given pregnancy. This capacity for fetal nutrition to minimize the growth response to transient ecologic fluctuations is defined here as intergenerational "phenotypic inertia," and is hypothesized to allow the fetus to cut through the "noise" of seasonal or other stochastic influences to read the "signal" of longer-term ecologic trends. As a mode of adaptation, phenotypic inertia may help the organism cope with ecologic trends too gradual to be tracked by conventional developmental plasticity, but too rapid to be tracked by natural selection. From an applied perspective, if a trait like fetal growth is designed to minimize the effects of short-term fluctuations by integrating information across generations, public health interventions may be most effective if focused not on the individual but on the matriline.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A supply–demand model of fetal energy sufficiency predicts lipid profiles in male but not female Filipino adolescents

OBJECTIVE

To test the hypothesis that the balance between fetal nutritional demand and maternal nutritional supply during pregnancy will predict lipid profiles in offspring measured in adolescence.

SUBJECTS AND METHODS

A total of 296 male and 307 female Filipino offspring (aged 14-16 y) and mothers enrolled in a longitudinal birth cohort study (begun in 1983-84) had lipid profiles measured. Data on maternal height (as a proxy for offspring growth potential and thus fetal nutritional demand) and third trimester maternal arm fat area (as a proxy for maternal supply) were used to create four groups hypothesized to reflect a gradient of fetal energy sufficiency.

RESULTS

As fetal energy sufficiency increased among males, there was a decrease in total cholesterol (TC) (P<0.05 for trend), low-density lipoprotein cholesterol (LDL-C), and the ratios of TC/HDL-C cholesterol and LDL-C/HDL-C (all P<0.001), while HDL-C increased (P<0.05). Similar associations were identified when lipid levels were modeled as dichotomous 'high-risk' cut-points used in cardiovascular disease prevention in adolescents. These relationships were stronger, or only present, among offspring of mothers in the lower half of the third trimester energy intake distribution, and were independent of the child's current adiposity, dietary energy and fat intake, maturity, household income, and birth weight. In females, the supply-demand model did not predict any lipid outcome or clinical risk criteria.

CONCLUSIONS

Our findings in males support the hypothesis that the balance between fetal nutritional demand and maternal nutritional supply has implications for future lipid profiles. The lack of significant associations in females adds to mounting evidence for sex differences in lipid metabolism programming, and may reflect sex differences in fetal nutritional demand.

SPONSORSHIP

The National Science Foundation, the Mellon Foundation, the Nestle Foundation, and the Emory University Internationalization Program.

Evaluation of a nutrition supplementation programme in the Northern Cape Province of South Africa

AIM

This study aimed at assessing the effectiveness regarding implementation and impact of a take-home nutrition supplementation programme, the Protein Energy Malnutrition (PEM) Scheme, that targets malnourished pre-school children and pregnant and lactating women in the Northern Cape Province of South Africa.

METHODOLOGY

In assessing implementation of the PEM Scheme, a cross-sectional descriptive study was undertaken over a 6-month period in the six regions of the Northern Cape Province. Interviews were conducted with programme managers and health personnel at clinics who were responsible for implementing the PEM Scheme. In assessing the impact of the PEM Scheme on growth, a retrospective review was done of the clinic records (including anthropometric data) of children enrolled in the PEM Scheme over a 1-year period.

RESULTS

About 76% of the budget allocated to the PEM Scheme had been utilised over the 1-year period. The budget for the following financial year was based solely on food supplements purchased in the previous year. Coverage of malnourished pre-school children and eligible pregnant and lactating women for enrolment was estimated to be 50% and 60%, respectively. Eighty-five per cent of health facilities in the province participated in the PEM Scheme. Some of the main problems identified included: lack of training, inappropriate targeting of certain groups, incorrect application especially of discharge criteria for pregnant and lactating women, inadequate assessment for nutrition-related disease, inadequate nutrition counselling and no standardised monitoring. Of the 319 children enrolled over a year, the mean age was 16.2 (standard deviation 16.2) months, 41% had been low-birth-weight and 18% had been diagnosed with tuberculosis. Ten per cent of the children with a weight-for-age Z-score of <-2 moved into the normal Z-score range after being on the PEM Scheme for a mean duration of 8 months. There was an overall improvement in the weight-for-age Z-scores of 25% of the sample, with a significant difference between the mean weight-for-age Z-scores at enrolment and follow-up This was mainly related to significant improvement in the mean weight-for-age Z-scores of children <2 years.

CONCLUSIONS

Numerous problems with the PEM Scheme have been identified which could have limited its impact. Recommendations are proposed for improving the effectiveness and impact of the PEM Scheme in the province.

Micronutrients and fetal growth

Fetal undernutrition affects large numbers of infants in developing countries, with adverse consequences for their immediate survival and lifelong health. It manifests as intrauterine growth retardation (IUGR), defined as birth weight <10th percentile, which probably underestimates the number failing to achieve full growth potential. Birth weight is a crude measure of the dynamic process of fetal growth and does not capture effects of fetal undernutrition on body composition and the development of specific tissues. The link between maternal nutrition and fetal nutrition is indirect. The fetus is nourished by a complex supply line that includes the mother's diet and absorption, endocrine status and metabolism, cardiovascular adaptations to pregnancy and placental function. Micronutrients are essential for growth, and maternal micronutrient deficiency, frequently multiple in developing countries, may be an important cause of IUGR. Supplementation of undernourished mothers with micronutrients has several benefits but there is little hard evidence of improved fetal growth. However, this has been inadequately tested. Most trials have only used single micronutrients and many were inconclusive because of methodological problems. Several food-based studies (some uncontrolled) suggest benefits from improving maternal dietary quality with micronutrient-dense foods. One trial of a multivitamin supplement (HIV-positive mothers, Tanzania) showed increased birth weight and fewer fetal deaths. Well-conducted randomized controlled trials of adequate sample size and including measures of effectiveness are needed in populations at high risk of micronutrient deficiency and IUGR and should include food-based interventions and better measurements of fetal growth, maternal metabolism, and long-term outcomes in the offspring.

Energy and protein intake in pregnancy

BACKGROUND

Gestational weight gain is positively associated with fetal growth, and observational studies of food supplementation in pregnancy have reported increases in gestational weight gain and fetal growth.

OBJECTIVES

To assess the effects of advice to increase or reduce energy or protein intake, or of actual energy or protein supplementation or restriction, during pregnancy on energy and protein intakes, gestational weight gain, and the outcome of pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (October 2002) and contacted researchers in the field.

SELECTION CRITERIA

Acceptably controlled trials of dietary advice to increase or reduce energy or protein intake, or of actual energy or protein supplementation or restriction, during pregnancy.

DATA COLLECTION AND ANALYSIS

Data were extracted by the authors from published reports, and supplemented by additional information from trialists contacted by the authors.

MAIN RESULTS

In five trials involving 1134 women, nutritional advice to increase energy and protein intakes was successful in achieving those goals, but no consistent benefit was observed on pregnancy outcomes. In 13 trials involving 4665 women, balanced energy/protein supplementation was associated with modest increases in maternal weight gain and in mean birth weight, and a substantial reduction in risk of small-for-gestational-age (SGA) birth. These effects did not appear greater in undernourished women. No significant effects were detected on preterm birth, but significantly reduced risks were observed for stillbirth and neonatal death. In two trials involving 1076 women, high-protein supplementation was associated with a small, nonsignificant increase in maternal weight gain but a nonsignificant reduction in mean birthweight, a significantly increased risk of SGA birth, and a nonsignificantly increased risk of neonatal death. In 3 trials involving 966 women, isocaloric protein supplementation was also associated with an increased risk of SGA birth. In three trials involving 384 women, energy/protein restriction of pregnant women who were overweight or exhibited high weight gain significantly reduced weekly maternal weight gain and mean birth weight but had no effect on pregnancy-induced hypertension or pre-eclampsia.

REVIEWER'S CONCLUSIONS

Dietary advice appears effective in increasing pregnant women's energy and protein intakes but is unlikely to confer major benefits on infant or maternal health. Balanced energy/protein supplementation improves fetal growth and may reduce the risk of fetal and neonatal death. High-protein or balanced protein supplementation alone is not beneficial and may be harmful to the infant.Protein/energy restriction of pregnant women who are overweight or exhibit high weight gain is unlikely to be beneficial and may be harmful to the infant.

Maternal nutrition and perinatal survival

The simple relationship between maternal macronutrient status and perinatal survival (increased macronutrient intake --> increased maternal weight and/or weight gain --> increased fetal growth --> improved survival) that is usually posited is no longer defensible. First, maternal weight and weight gain are remarkably resistant to either dietary advice or supplementation; further, increased birth weight attributable to maternal nutrition does not necessarily increase perinatal survival (because prepregnant weight is positively associated with both birth weight and higher perinatal mortality). Finally, whereas dietary supplements during pregnancy may have a modest effect on birth weight in nonfamine conditions (by contrast with a large effect in famine or near-famine conditions), their impact is not mediated by maternal energy deposition. Rather, the component of maternal weight gain associated with accelerated fetal growth is maternal water (presumably plasma) volume.

Effects of altitude versus economic status on birth weight and body shape at birth

The compelling evidence linking small size at birth with later cardiovascular disease has renewed and amplified a clinical and scientific interest in the determinants of fetal growth. Although the effects of maternal nutrition on fetal growth have been extensively studied, comparatively little is known about the effects of maternofetal hypoxia. This study tested the hypothesis that in highland regions, high altitude rather than maternal economic status is associated with reduced and altered fetal growth by investigating the effects of high altitude versus economic status on birth weight and body shape at birth in Bolivia. Bolivia is geographically and socioeconomically unique. It contains several highland (>3500 m above sea level) and lowland (<500 m) cities that are inhabited by very economically divergent populations. Birth weight, body length, and head circumference were compared between a high- (n = 100) and low- (n = 100) income region of La Paz (3649 m; largest high-altitude city) and a high- (n = 100) and low- (n = 100) income region of Santa Cruz (437 m; largest low-altitude city). In addition, the frequency distribution across the continuum of birth weights was plotted for babies born from high- and low-income families in La Paz and Santa Cruz. Mean birth weights were lower in babies from La Paz than in babies from Santa Cruz in both high- and low-income groups. The cumulative frequency curve across all compiled birth weights was shifted to the left in babies from La Paz compared with those from Santa Cruz, regardless of economic status. The frequency of low birth weight (<2500 g) was higher in babies from La Paz than from Santa Cruz in both high- and low-income groups. In addition, at high altitude but not at low altitude, high income was associated with an increase in the head circumference:birth weight ratio. These findings suggest that high altitude rather than economic status is associated with low birth weight and altered body shape at birth in babies from Bolivia.

Maternal sociocultural status: a novel assessment of risk for the birth of small for gestational age, low birth weight infants

OBJECTIVES

We assessed the significance of material sociocultural status within the family as a risk factor for low birth weight-small for gestational age (LBW-SGA) births using a novel scoring system and also isolated related medical risk factors.

METHODS

A prospective matched pairs case control study of 396 LBW-SGA infants (cases) and 396 term, appropriate for gestational age infants (controls) was set up.

RESULTS

Low maternal sociocultural status (p = 0.02) was significantly associated with LBW-SGA births as were nonregistration for antenatal care (p = 0.001), maternal weight at delivery < 50 kg (p < 0.0001), antepartum hemorrhage/preeclampsia (p < 0.01), primigravidity and previous small baby (p <0001). Other risk factors included birth interval < 24 m (p < 0.001) and poor maternal or paternal education (p < 0.05). Conditional logistic regression identified maternal weight at delivery < 50 kg (OR 4.8, 95% C.I. 3.0-7.6), lack of antenatal care (OR 2.0, 95% C.I. 1.4-2.9), antepartum hemorrhage/preeclampsia (OR 4.3, 95% C.I. 1.7-10.8) and previous small baby (OR 4.3, 95% C.I. 2.1-8.9) as independent risk factors.

CONCLUSIONS

Low sociocultural status of the mother within the family is significantly associated with having a LBW-SGA baby. Further studies are warranted to study this risk factor.

Decrease in birth weight in relation to maternal bone-lead burden

OBJECTIVES

Birth weight predicts infant survival, growth, and development. Previous research suggests that low levels of fetal lead exposure, as estimated by umbilical cord blood-lead levels at birth, may have an adverse effect on birth weight. This report examines the relationship of lead levels in cord blood and maternal bone to birth weight.

METHODS

Umbilical cord and maternal venous blood samples and anthropometric and sociodemographic data were obtained at delivery and 1-month postpartum. Blood-lead levels were analyzed by atomic absorption spectrophotometry. Maternal tibia and patella lead levels were determined at 1-month postpartum with use of a spot-source 109Cd K-X-ray fluorescence instrument. The relationship between birth weight and lead burden was evaluated by multiple regression with control of known determinants of size at birth.

RESULTS

Data on all variables of interest were obtained for 272 mother-infant pairs. After adjustment for other determinants of birth weight, tibia lead was the only lead biomarker clearly related to birth weight. The decline in birth weight associated to increments in tibia lead was nonlinear and accelerated at the highest tibia lead quartile. In the upper quartile, neonates were on average, 156 grams lighter than those in the lowest quartile. Other significant birth weight predictors included maternal nutritional status, parity, education, gestational age, and smoking during pregnancy.

CONCLUSIONS

Our results indicate that bone-lead burden is inversely related to birth weight. Taken together with other research indicating that lead can mobilize from bone into plasma without detectable changes in whole blood lead, these findings suggest that bone lead might be a better biomarker than blood lead. Because lead remains in bone for years to decades, mobilization of bone lead during pregnancy may pose a significant fetal exposure with health consequences, long after maternal external lead exposure has declined.

Timing in prenatal nutrition: a reprise of the Dutch Famine Study

The array of results discussed in this paper is assembled by stage of gestation in the following table (Table 1). We must allow some uncertainty for some outcomes as to the precise stages of gestation in which they originate. For instance, with obesity, the effects of famine exposure may extend beyond the first trimester into the second. Yet, the table is perhaps sufficient in itself to support the point with which the paper opened, namely, that stage of development is crucial to the appreciation of the effects of prenatal nutrition.

Neonatal mortality and the economy revisited

The association between economic contraction and neonatal mortality previously reported in this Journal is retested using methods and data that respond to criticisms of aggregate time-series work. Results suggest that the risk of neonatal mortality among birth cohorts of black males in the Los Angeles County and Orange County metropolitan areas is increased by unexpectedly low levels of employment in the second trimester. The argument is made that the strength of the effect is probably not sufficient to make the case for stimulating regional economies more compelling.

Ethnic and environmental factors affecting fetal growth in Papua New Guinea

We studied 738 live singleton births in Papua New Guinea to examine the contribution of ethnic origin and environmental factors to birth weight and gestation. Maternal history, examination and post-partum anthropometry, infant anthropometry and clinical gestational assessment were performed, and placental blood slides and histology were examined. Mothers from Highlands provinces who delivered on the coast had larger babies (mean birthweight 3.34 SD 0.48 kg) than either indigenous coastal mothers (mean 3.10 SD 0.51 kg) or those migrating to Port Moresby from other coastal regions (mean 3.14 SD 0.51 kg). This was due to a combination of longer gestation and better intrauterine growth (assessed by birthweight standard deviation scores). Gestation was slightly longer in Highlands mothers delivering on the coast compared with those delivering in the Highlands, but birthweight standard deviation scores were unchanged. Malarial infection of the placenta was almost never found. Stepwise regression analysis showed that parity, maternal height, Highlands origin and maternal body mass index (weight/height2) were all significant predictors of birthweight standard deviation score, while maternal body mass index and Highlands origin were predictors of gestational length. We conclude that Highland mothers have a tendency to deliver heavier babies, and do not demonstrate the fetal growth-retarding effects of altitude seen in other races. Although the incidence of low birthweight was only 7.1% in our study, we found that indices of maternal nutrition were predictors of birth weight.

The effect of nutritional intake on outcome of pregnancy in smokers and non-smokers

The relationship between nutrient intake and pregnancy outcome (adjusted birth weight and gestational age) was investigated in randomly selected non-smokers (n97) and in heavy smokers (15 + cigarettes/d) (n72) booking for ante-natal care at a hospital in South London. Weighted dietary intakes (7d) were obtained at 28 and 36 weeks gestation. Birth weight was adjusted for gestational age, maternal height, parity and sex of infant. Compared with non-smokers, intakes of micronutrients and fibre were lower in smokers at both 28 and 36 weeks, and smokers reduced their intakes more in late pregnancy. The babies of smokers had a lower adjusted birth weight but there was no difference in length of gestation between smokers and non-smokers. After controlling for smoking, social class and alcohol consumption, nutrient intakes at 28 weeks were found to have no effect on adjusted birth weight. However, intakes of protein, zinc, riboflavin and thiamin at 36 weeks, and the change in intakes of these nutrients (plus iron) between 28 and 36 weeks, had independent positive effects on birth weight. Some of the effect of smoking on birth weight appeared to be mediated through differences in nutrient intakes. Smoking explained 14.3% of the variance in birth weight in this population and a further 2.4-7.2% was explained by change in nutrient intakes between 28 and 36 weeks. It is recommended that women in pregnancy do not reduce their dietary intakes in late pregnancy.

Psychosocial influences on new born outcomes: a controlled prospective study

This paper reports the results of a prospective investigation of 100 women during their pregnancies to test the hypothesis that social and psychological factors influence pregnancy outcome after controlling for demographic, biomedical, and lifestyle variables. Subjects completed questionnaires that assessed family social supports, life events, and anxiety. In addition, data were collected on general biomedical and pregnancy risk, lifestyle practices including smoking and drinking, as well as demographic information. Four infant outcomes, birthweight, gestational age, and 1 and 5 min Apgar scores, were studied via hierarchical multiple regression analyses for their relationship to the social and psychological variables, after controlling for all other sets of variables. The results of these analyses showed that life events stress accounted for significant variation in birthweight, and social supports and anxiety were associated with the two pediatric Apgar scores. Gestational age bore a simple relationship to anxiety, with higher anxiety predictive of lower gestational age. Further analyses revealed that women with either low social supports or high anxiety were, on the average, younger, more often single, of lower education level, had less income, smoked more, and had higher general biomedical risk than women with adequate social supports or lower anxiety. This suggests the multiple ways in which social and psychological risk factors may be related to pregnancy outcome and emphasizes the need for well controlled studies in this area.