Alison D. Gernand

Maternal Serum 25-Hydroxyvitamin D and Measures of Newborn and Placental Weight in a U.S. Multicenter Cohort Study

CONTEXT Inconsistent associations between maternal vitamin D status and fetal size have been published in small studies. OBJECTIVE Our objective was to examine the association between maternal 25-hydroxyvitamin D [25(OH)D] levels and measures of newborn and placental weight. DESIGN AND SETTING We measured maternal 25(OH)D in mothers from the Collaborative Perinatal Project, an observational cohort conducted in 12 U.S. medical centers from 1959 to 1965. PARTICIPANTS Women delivering singleton, term, live births with 25(OH)D measured at a gestation of 26 wk or less (n = 2146). MAIN OUTCOME MEASURES Birth weight, ponderal index, placental weight, the placental to fetal weight ratio, and small for gestational age were measured. Hypotheses were formulated after data collection. RESULTS After confounder adjustment, mothers with 25(OH)D of 37.5 nmol/liter or greater gave birth to newborns with 46 g [95% confidence interval (CI), 9-82 g] higher birth weights and 0.13 cm (0.01-0.25 cm) larger head circumferences compared with mothers with less than 37.5 nmol/liter. Birth weight and head circumference rose with increasing 25(OH)D up to 37.5 nmol/liter and then leveled off (P < 0.05). No association was observed between 25(OH)D and ponderal index, placental weight, or the placental to fetal weight ratio. Maternal 25(OH)D of 37.5 nmol/liter or greater vs. less than 37.5 nmol/liter in the first trimester was associated with half the risk of small for gestational age (adjusted odds ratio 0.5; 95% CI 0.3-0.9), but no second-trimester association was observed. CONCLUSIONS Maternal vitamin D status is independently associated with markers of physiological and pathological growth in term infants. Adequately powered randomized controlled trials are needed to test whether maternal vitamin D supplementation may improve fetal growth.

Nutrition Knowledge Predicts Eating Behavior of All Food Groups "except" Fruits and Vegetables among Adults in the Paso del Norte Region: Que Sabrosa Vida.

OBJECTIVE To examine the association between nutrition knowledge and eating behavior in a predominantly Mexican American population on the Texas-Mexico border. DESIGN Cross-sectional using data from the baseline survey of the Qué Sabrosa Vida community nutrition initiative. SETTING El Paso and surrounding counties in Texas. PARTICIPANTS Data gathered in 2000 using random-digit dialing telephone survey. Response rate was 42.6% and final sample size was 963. MAIN OUTCOME MEASURES Knowledge of recommended servings of food items was the independent variable and number of servings of food items consumed was the dependent variable. DATA ANALYSIS Multiple logistic regression was used to examine the association between nutrition knowledge and eating behavior. RESULTS 74% of the population was Mexican American. Nutrition knowledge was a significant predictor of eating behavior for grains (odds ratio [OR] = 6.42; 95% confidence interval [CI]: 2.4, 17.1), dairy (OR = 2.25; 95% CI: 1.5, 3.4), meats (OR = 2.02; 95% CI: 1.5, 2.8), beans (OR = 8.18; 95% CI: 5.1, 13.0), water (OR = 2.49; 95% CI: 1.7, 3.6), but not for fruits and (nonstarchy) vegetables (OR = 1.69; 95% CI: 0.89, 3.2). CONCLUSIONS AND IMPLICATIONS Nutrition knowledge predicts eating behavior for all food groups except fruits and vegetables. The role of cultural factors in eating behavior should be investigated to elucidate this finding. Results have implications for developing nutrition education programs for Mexican Americans.

Micronutrient deficiencies in pregnancy worldwide: health effects and prevention

Micronutrients, vitamins and minerals accessible from the diet, are essential for biologic activity. Micronutrient status varies widely throughout pregnancy and across populations. Women in low-income countries often enter pregnancy malnourished, and the demands of gestation can exacerbate micronutrient deficiencies with health consequences for the fetus. Examples of efficacious single micronutrient interventions include folic acid to prevent neural tube defects, iodine to prevent cretinism, zinc to reduce risk of preterm birth, and iron to reduce the risk of low birth weight. Folic acid and vitamin D might also increase birth weight. While extensive mechanistic and association research links multiple antenatal micronutrients with plausible materno–fetal health advantages, hypothesized benefits have often been absent, minimal or unexpected in trials. These findings suggest a role for population context in determining health responses and filling extensive gaps in knowledge. Multiple micronutrient supplements reduce the risks of being born with low birth weight, small for gestational age or stillborn in undernourished settings, and justify micronutrient interventions with antenatal care. Measurable health effects of gestational micronutrient exposure might persist into childhood but few data exists on potential long-term benefits. In this Review, we discuss micronutrient intake recommendations, risks and consequences of deficiencies, and the effects of interventions with a particular emphasis on offspring.

Maternal vitamin D status and small-for-gestational-age offspring in women at high risk for preeclampsia.

OBJECTIVE: To examine the association between second-trimester maternal serum 25-hydroxyvitamin D concentrations and risk of small for gestational age (SGA) in singleton live births. METHODS: We assayed serum samples at 12–26 weeks of gestation for 25-hydroxyvitamin D in a sample of participants in a multicenter clinical trial of low-dose aspirin for the prevention of preeclampsia in high-risk women (n=792). Multivariable log-binomial regression models were used to assess the association between 25-hydroxyvitamin D and risk of SGA (birth weight less than the 10th percentile for gestational age) after adjustment for confounders including maternal prepregnancy obesity, race, treatment allocation, and risk group. RESULTS: Thirteen percent of neonates were SGA at birth. Mean (standard deviation) 25-hydroxyvitamin D concentrations were lower in women who delivered SGA (57.9 [29.9] nmol/L) compared with non-SGA neonates (64.8 [29.3] nmol/L, P=.028). In adjusted models, 25-hydroxyvitamin D concentrations of 50–74 nmol/L and 75 nmol/L or greater compared with less than 30 nmol/L were associated with 43% (95% confidence interval [CI] 0.33–0.99) and 54% (95% CI 0.24–0.87) reductions in risk of SGA, respectively. Race and maternal obesity each modified this association. White women with 25-hydroxyvitamin D 50 nmol/L or greater compared with less than 50 nmol/L had a 68% reduction in SGA risk (adjusted risk ratio 0.32, 95% CI 0.17–0.63) and nonobese women with 25-hydroxyvitamin D 50 nmol/L or greater compared with less than 50 nmol/L had a 50% reduction in SGA risk (adjusted risk ratio 0.50, 95% CI 0.31–0.82). There was no association between 25-hydroxyvitamin D and risk of SGA in black or obese mothers. CONCLUSION: Maternal vitamin D status in the second trimester is associated with risk of SGA among all women and in the subgroups of white and nonobese women. LEVEL OF EVIDENCE: II

Validity of Birth Certificate-Derived Maternal Weight Data

BACKGROUND Studies using vital records-based maternal weight data have become more common, but the validity of these data is uncertain. METHODS We evaluated the accuracy of prepregnancy body mass index (BMI) and gestational weight gain (GWG) reported on birth certificates using medical record data in 1204 births at a teaching hospital in Pennsylvania from 2003 to 2010. Deliveries at this hospital were representative of births statewide with respect to BMI, GWG, race/ethnicity, and preterm birth. Forty-eight strata were created by simultaneous stratification on prepregnancy BMI (underweight, normal weight/overweight, obese class 1, obese classes 2 and 3), GWG (<20th, 20-80th, >80th percentile), race/ethnicity (non-Hispanic white, non-Hispanic black), and gestational age (term, preterm). RESULTS The agreement of birth certificate-derived prepregnancy BMI category with medical record BMI category was highest in the normal weight/overweight and obese class 2 and 3 groups. Agreement varied from 52% to 100% across racial/ethnic and gestational age strata. GWG category from the birth registry agreed with medical records for 41-83% of deliveries, and agreement tended to be the poorest for very low and very high GWG. The misclassification of GWG was driven by errors in reported prepregnancy weight rather than maternal weight at delivery, and its magnitude depended on prepregnancy BMI category and gestational age at delivery. CONCLUSIONS Maternal weight data, particularly at the extremes, are poorly reported on birth certificates. Investigators should devote resources to well-designed validation studies, the results of which can be used to adjust for measurement errors by bias analysis.

Aflatoxin exposure during the first 1000 days of life in rural South Asia assessed by aflatoxin B1-lysine albumin biomarkers

Aflatoxin B1 is a potent carcinogen, occurring from mold growth that contaminates staple grains in hot, humid environments. In this investigation, aflatoxin B1-lysine albumin biomarkers were measured by mass spectrometry in rural South Asian women, during the first and third trimester of pregnancy, and their children at birth and at two years of age. These subjects participated in randomized community trials of antenatal micronutrient supplementation in Sarlahi District, southern Nepal and Gaibandha District in northwestern Bangladesh. Findings from the Nepal samples demonstrated exposure to aflatoxin, with 94% detectable samples ranging from 0.45 to 2939.30 pg aflatoxin B1-lysine/mg albumin during pregnancy. In the Bangladesh samples the range was 1.56 to 63.22 pg aflatoxin B1-lysine/mg albumin in the first trimester, 3.37 to 72.8 pg aflatoxin B1-lysine/mg albumin in the third trimester, 4.62 to 76.69 pg aflatoxin B1-lysine/mg albumin at birth and 3.88 to 81.44 pg aflatoxin B1-lysine/mg albumin at age two years. Aflatoxin B1-lysine adducts in cord blood samples demonstrated that the fetus had the capacity to convert aflatoxin into toxicologically active compounds and the detection in the same 2-year-old children illustrates exposure over the first 1000 days of life.

Maternal serum 25-hydroxyvitamin D and placental vascular pathology in a multicenter US cohort

BACKGROUND Maternal vitamin D deficiency has been linked to fetal growth restriction, but the underlying mechanisms are unclear. OBJECTIVE We tested the hypothesis that poor maternal 25-hydroxyvitamin D [25(OH)D] is associated with increased risk of placental vascular pathology. DESIGN Maternal serum 25(OH)D was measured at ≤26 wk of gestation in a random subcohort of term, singleton infants in the Collaborative Perinatal Project (1959-1966; n = 2048). A dichotomous vascular construct was created from the presence of any of 12 pathologies identified on placental examinations, including evidence of placental abruption, infarction, hypoxia, decidual vasculopathy, or thrombosis of fetal vessels (n = 240 cases). RESULTS The relation between 25(OH)D and vascular pathology was modified by infant sex (P = 0.003). A maternal 25(OH)D concentration ≥80 compared with <50 nmol/L was associated with 49% lower risk of pathology in boys [adjusted OR (95% CI): 0.27, 0.95] after conditioning on study site. No associations were observed between maternal 25(OH)D and pathology in mothers with female offspring. Subsequent analyses showed that, in pregnancies with a female fetus, vascular pathology was associated with a reduced birth-weight z score when the mothers 25(OH)D concentration was <30 nmol/L (β: -0.73; 95% CI: -1.17, -0.30). No association was observed between pathology and birth weight in mothers of female offspring with 25(OH)D concentrations ≥30 nmol/L or in boys, regardless of maternal 25(OH)D status. CONCLUSIONS Our findings suggest complex relations between vitamin D, placental vascular pathology, and birth weight that differ by infant sex. Maternal vitamin D status may be beneficial for male and female offspring through different mechanisms.

Maternal Weight and Body Composition during Pregnancy Are Associated with Placental and Birth Weight in Rural Bangladesh

Placental growth is a strong predictor of fetal growth, but little is known about maternal predictors of placental growth in malnourished populations. Our objective was to investigate in a prospective study the associations of maternal weight and body composition [total body water (TBW) estimated by bioelectrical impedance and fat and fat-free mass derived from upper arm fat and muscle areas (UAFA, UAMA)] and changes in these with placental and birth weights. Within a cluster-randomized trial of maternal micronutrient supplementation, a subsample of 350 women was measured 3 times across gestation. Longitudinal analysis was used to examine independent associations of ∼10-wk measurements and ∼10-20 wk and ∼20-32 wk changes with birth outcomes. Weight, TBW, and UAMA, but not UAFA, at ∼10 wk were each positively and independently associated with placental weight and birth weight (P < 0.05). Of the maternal ∼10-20 wk changes in measurements, only TBW change and placental weight, and maternal weight and birth weight were positively associated (P < 0.05). Gains in weight, TBW, and UAMA from 20 to 32 wk were positively and UAFA gain was negatively associated with placental weight (P ≤ 0.01). Gains in weight and UAMA from 20 to 32 wk were positively associated with birth weight (P ≤ 0.01). Overall, higher maternal weight and measures of fat-free mass at ∼10 wk gestation and gains from 20 to 32 wk are independently associated with higher placental and birth weight.

Maternal vitamin D status and infant anthropometry in a US multi-centre cohort study

Abstract Background: Maternal vitamin D status in pregnancy is linked to foetal growth and may impact infant growth. Aim: This study examined the association between maternal vitamin D status and infant anthropometry. Subjects and methods: Data came from n = 2473 mother–child pairs from the 12-site US Collaborative Perinatal Project (1959–1965). Maternal serum 25-hydroxyvitamin D (25(OH)D) was measured at ≤ 26 weeks gestation. Multivariate-adjusted linear mixed models were used to relate maternal vitamin D status to infant z-scores for length (LAZ), head circumference (HCZ), weight (WAZ) and BMI (BMIZ), measured at birth and 4, 8 and 12 months. Results: Infants with maternal 25(OH)D ≥30 nmol/L vs <30 nmol/L had LAZ and HCZ measures 0.13 (95% CI = 0.03–0.23) and 0.20 (95% CI = 0.11–0.28) units higher, respectively, across the first year of life. Similar differences in WAZ and BMIZ at birth were resolved by 12 months of age due to interactions indicating steeper age slopes in infants with maternal 25(OH)D <30 nmol/L. Conclusion: Low maternal vitamin D status was associated with deficits at birth in infant weight and BMI that were recouped across the first year of life; associations with reduced measures of linear and skeletal growth were sustained from birth to 12 months.

Maternal vitamin D status, prolonged labor, cesarean delivery and instrumental delivery in an era with a low cesarean rate.

Objective:To examine the association between maternal 25-hydroxyvitamin D (25(OH)D) and adverse labor and delivery outcomes.Study Design:We measured serum 25(OH)D at ⩽26 weeks gestation in a random subsample of vertex, singleton pregnancies in women who labored (n=2798) from the 12-site Collaborative Perinatal Project (1959 to 1966). We used labor and delivery data to classify cases of adverse outcomes.Result:Twenty-four percent of women were vitamin D deficient (25(OH)D <30 nmol l−1), and 4.5, 3.3, 1.9 and 7.5% of women had prolonged stage 1 labor, prolonged stage 2 labor, primary cesarean delivery or indicated instrumental delivery, respectively. After adjustment for prepregnancy body mass index, race and study site, 25(OH)D concentrations were not associated with risk of prolonged stage 1 or 2, cesarean delivery or instrumental delivery.Conclusion:Maternal vitamin D status at ⩽26 weeks was not associated with risk of prolonged labor or operative delivery in an era with a low cesarean rate.