MATERNAL BLOOD PRESSURE IN RELATION TO LOW BIRTH WEIGHT AND THE EFFECT OF A NUTRITIONAL SUPPLEMENT

Abstract

Background: Hypertensive disorders of pregnancy impact over 10% of pregnancies worldwide, while increasing the risk of low birth weight. Research is conflicting on the effect of nutrient supplementation on hypertension during pregnancy. The cutoffs to define hypertension have also recently changed to include a lower systolic blood pressure, and little research has examined the association between the newly proposed blood pressure cutoffs and low birth weight. Objectives: Our objectives were to 1) evaluate the impact of prenatal lipid-based nutrient supplement consumption on maternal blood pressure; and 2) assess the association between maternal blood pressure during early and late pregnancy with infant birth weight. Study Design: A total of 1320 pregnant women ≤ 20 weeks gestation in Ghana were randomized to receive daily either: 1) iron and folic acid, 2) multiple micronutrients, or 3) a small-quantity lipid-based nutrient supplement. Gestational age was determined by ultrasound and newborn weight measured at delivery. Blood pressure was measured at enrollment and 36 weeks gestation. The effect of the consumption of a lipid-based nutrient supplement on maternal blood pressure was analyzed using ANOVA and ANCOVA, and associations between maternal hypertension and birth weight were examined by linear and logistic regressions. Results: Mean (±SD) systolic and diastolic blood pressure at 36 weeks gestation were 110±11 and 63±8 mmHg, respectively. The means for systolic and diastolic blood pressure did not differ by supplementation group, (p-value > 0.05). The prevalence of high systolic blood pressure (≥ 130 mmHg) and high diastolic blood pressure (≥ 80 mmHg) at enrollment was 6.6% and 3.6% and there was a significant association between higher diastolic blood pressure and lower birth weight at enrollment (β = - 0.086, SE = 0.001 ; p = 0.011) in adjusted models. High diastolic blood pressure significantly increased the risk for low birth weight (odds ratio = 2.99, 95% confidence interval 1.04-8.62; p=0.042) in adjusted models. At 36 weeks, the prevalence of high systolic and high diastolic blood pressure was 4.3% and 2.4% and lower birth weight was significantly associated with higher systolic (β = -0.074, SE = 0.00 ; p = 0.029) and diastolic (β = -0.094, 0.00; p = 0.006) blood pressure. Diastolic blood pressure was significantly associated with an increased risk of low birth weight (OR=4.14, 95% CI=0.020). Conclusions: Daily consumption of a lipid-based nutrient supplement during pregnancy did not have a significant effect on maternal hypertension compared with iron and folic acid or