Xinhua Chen

Vitamin D intake during pregnancy : Association with maternal characteristics and infant birth weight

BACKGROUNDnVitamin D insufficiency is beginning to be recognized as a public health problem. It is plausible that some portion of the lower Vitamin D levels which characterize minority populations is related to diet.nnnAIMSnWe examined and described total Vitamin D intake during pregnancy from the mean of three 24-hour recalls plus use of dietary supplements.nnnSTUDY DESIGNnProspective cohort.nnnSUBJECTSn2251 low income, minority gravidae from Camden, New Jersey, USA.nnnOUTCOME MEASURESnDifferences in total Vitamin D intake by maternal ethnicity. BMI and other factors (age, parity) and associations of total Vitamin D intake with gestation duration and birth weight adjusted for gestation.nnnRESULTS AND CONCLUSIONSnTotal Vitamin D intake was significantly lower for minority gravidae (African American, and Hispanic, mainly Puerto Rican), for parous women, and for women with pregravid BMIs consistent with obesity or being overweight. After control for energy, other nutrients, and other potential confounding variables, total intake of Vitamin D was associated with increased infant birth weight; gravidae below the current adequate intake (<5 microg/day or 200 IU) had infants with significantly lower birth weights (p<0.05). Additional intake of Vitamin D may be of importance since higher intake is associated with increased birth weight in a population at risk of adverse pregnancy outcomes.

Maternal Vitamin D Status and Delivery by Cesarean

We examined the association of vitamin D deficiency to risk of cesarean delivery using prospective data in a cohort of 1153 low income and minority gravidae. Circulating maternal 25-hydroxyvitamin D and intact parathyroid hormone were measured at entry to care 13.73 ± 5.6 weeks (mean ± SD). Intake of vitamin D and calcium was assessed at three time points during pregnancy. Using recent Institute of Medicine guidelines, 10.8% of the gravidae were at risk of vitamin D deficiency, and 23.8% at risk of insufficiency. Maternal 25-hydroxyvitamin D was related positively to vitamin D and calcium intakes and negatively to circulating concentrations of parathyroid hormone. Risk for cesarean delivery was increased significantly for vitamin D deficient women; there was no increased risk for gravidae at risk of insufficiency. When specific indications were examined, vitamin D deficiency was linked to a 2-fold increased risk of cesarean for prolonged labor. Results were the similar when prior guidelines for vitamin D deficiency (25(OH)D < 37.5nmol/L) and insufficiency (37.5–80 nmol/L) were utilized.

Association of Elevated, Free Fatty Acids During Late Pregnancy With Preterm Delivery

OBJECTIVE: To examine the association between moderately elevated maternal plasma free fatty acids (FFAs) during late pregnancy and preterm delivery. METHODS: In a prospective observational cohort with 523 healthy pregnant women, fasting plasma FFAs were measured during the third trimester. Socioeconomic, demographic, and anthropometric measures were collected at entry to prenatal care, and pregnancy outcomes were abstracted from medical record at delivery. RESULTS: After control for confounders including prepregnant body mass index (multiple logistic regression analysis), women who had moderately elevated plasma FFAs (in the highest tertile), showed a greater than threefold increased risk of preterm delivery (adjusted odds ratio (AOR) 3.49, 95% (CI) 1.73–7.03, P<.001). The associations persisted in women who had spontaneous preterm delivery (AOR 2.35, 95% CI 1.05–5.28, P<.05) and after excluding women with gestational diabetes mellitus and preeclampsia (AOR 3.30, 95% CI 1.38–7.87, P<.01). Additional stratified analyses showed that the association of high maternal FFAs and increased risk of preterm delivery was independent of prepregnant obesity. CONCLUSION: Elevated fasting plasma FFA levels at 30 weeks of gestation were associated with an increased risk of preterm delivery. This effect was independent of prepregnant obesity and several other known risk factors for preterm delivery, including cigarette smoking, ethnicity, and prior preterm delivery. These data may have important clinical significance because they provide a possible link between preterm delivery and high lipid levels, a known risk factor for cardiovascular disease. LEVEL OF EVIDENCE: II

Insulin and the "thrifty" woman: the influence of insulin during pregnancy on gestational weight gain and postpartum weight retention.

Objectives: To test Neels hypothesis among pregnant women: a high maternal insulin concentration in early pregnancy increases the risk of weight gain, overweight, and obesity among nondiabetic, low-income gravidas of racial and ethnic minority groups from Camden, New Jersey. Methods: Fasting insulin was obtained from 461 gravidas at entry to prenatal care. Insulin quartile was related to rate of gestational weight gain and excess weight gain during pregnancy (≥90th percentile) and to retained weight and excess weight retention at 4–6 weeks postpartum (≥90th percentile). The relationship between excess retained weight and excessive insulin increase (≥90th percentile) was also examined. Results: Compared with gravidas with an insulin concentration in the lowest three quartiles, gravidas with the highest insulin quartile had a significantly higher rate of gestational weight gain (nonobese women only) and average weight retained postpartum (all women). Compared with an insulin concentration in the lowest three quartiles, the highest insulin quartile was associated with a 2.05-fold (95% confidence interval [CI] = 1.07–3.93) risk of an excessive rate of gestational weight gain and a 3.58-fold (95% CI = 1.87–6.84) risk of excess weight retained postpartum. Excess weight retained postpartum was linked to a 2.63-fold (95% CI = 1.00–6.89) risk of an excessive increase in insulin concentration postpartum. Conclusions: Our results support Neels hypothesis and suggest that a high maternal insulin concentration is associated with increased gestational weight gain and increased weight retention postpartum. High insulin concentration may contribute to pregnancy-related changes in weight and thus may be linked to maternal overweight and obesity postpartum as well as to future risk of gestational and Type 2 diabetes mellitus.

Vitamin D, secondary hyperparathyroidism, and preeclampsia

BACKGROUNDnSecondary hyperparathyroidism, which is defined by a high concentration of intact parathyroid hormone when circulating 25-hydroxyvitamin D [25(OH)D] is low, is a functional indicator of vitamin D insufficiency and a sign of impaired calcium metabolism. Two large randomized controlled trials examined effects of calcium supplementation on preeclampsia but did not consider the vitamin D status of mothers.nnnOBJECTIVEnWe examined the association of secondary hyperparathyroidism with risk of preeclampsia.nnnDESIGNnCirculating maternal 25-hydroxyvitamin D [25(OH)D] and intact parathyroid hormone were measured at entry to care (mean ± SD: 13.7 ± 5.7 wk) using prospective data from a cohort of 1141 low-income and minority gravidae.nnnRESULTSnSecondary hyperparathyroidism occurred in 6.3% of the cohort and 18.4% of women whose 25(OH)D concentrations were <20 ng/mL. Risk of preeclampsia was increased 2.86-fold (95% CI: 1.28-, 6.41-fold) early in gestation in these women. Gravidae with 25(OH)D concentrations <20 ng/mL who did not also have high parathyroid hormone and women with high parathyroid hormone whose 25(OH)D concentrations were >20 ng/mL were not at increased risk. Intact parathyroid hormone was related to higher systolic and diastolic blood pressures and arterial pressure at week 20 before clinical recognition of preeclampsia. Energy-adjusted intakes of total calcium and lactose and circulating 25(OH)D were correlated inversely with systolic blood pressure or arterial pressure and with parathyroid hormone.nnnCONCLUSIONnSome women who are vitamin D insufficient develop secondary hyperparathyroidism, which is associated with increased risk of preeclampsia.

Maternal Diet, C-Reactive Protein, and the Outcome of Pregnancy

Objective: To examine the association of high-sensitivity C-reactive protein (hsCRP), a systemic biomarker for the inflammatory process at entry to care, with pregnancy-induced hypertension/preeclampsia, adverse outcomes of pregnancy, and the maternal diet. Design: Random sample (N = 520) with normal glucose tolerance from a large prospective cohort study of urban, low income, minority gravidae. Results: During pregnancy, the highest tertile of hsCRP (range, 7.06–137.41 mg/L) was associated with significantly increased risks for early preterm delivery (<34 weeks). However, after stratification by maternal pregravid body mass index (BMI), risk for early preterm delivery <34 weeks (adjusted odds ratios [AOR] = 3.58, 95% confidence interval [CI] = 1.05–12.27), and pregnancy-induced hypertension (AOR = 2.66, 95% CI = 1.03–6.86) including preeclampsia (AOR = 2.72, 95% CI = 1.08–6.85) was shown to be specific to lean women (BMI <25) with high hsCRP. Increased hsCRP was unrelated to risk among overweight and obese gravidae. We found high hsCRP to be associated with diet. After stratification by BMI, dietary differences (higher intakes of protein and cholesterol with a lower intake of carbohydrate and a higher entry dietary glycemic index) were associated with increased hsCRP only among lean gravidae and not among those who were overweight or obese. Conclusions: High hsCRP is a diet-related biomarker for serious complications and poor outcome in lean women with normal glucose tolerance.