Preconception Micronutrient Supplementation Affects Maternal Body Mass Index Post-Partum: A Randomized Controlled Trial in Vietnam

While there is growing evidence on the role of preconception nutrition for birth outcomes, very few studies have evaluated the effects of nutrition interventions during the preconception period on maternal health. This study evaluates the impact of preconception weekly multiple micronutrients (MM) or iron and folic acid (IFA) supplementation compared to FA alone on maternal nutritional status through 6–7y post-partum (PP). We followed women who participated in a randomized controlled trial of preconception supplementation in Vietnam and delivered live offspring (n = 1599). Women received weekly supplements containing either 2800 μg FA only, 60 mg iron and 2800 μg FA, or MM (15 micronutrients including IFA), from baseline until conception; followed by daily prenatal IFA supplements until delivery. Anthropometric measurements were obtained at recruitment and at 2 and 6–7 y PP. Group comparisons were done using ANOVA or chi-square tests. The groups were similar for baseline (preconception) maternal and offspring birth characteristics. Mean (SD) Body Mass Index (BMI; kg/m2) increased from 19.6 (2.1) at baseline, to 20.4 (2.4) and 21.6 (2.8) at 2 and 6–7 y PP (n = 931). The prevalence of overweight (BMI ≥ 23.5 kg/m2) also increased from 4.7% to 9% and 21%, at baseline, 2, and 6–7 years PP respectively, while underweight (BMI < 18.5 kg/m2) declined from 31.4% to 21.4% and 10%, respectively. At 6–7 y PP, we found significant differences (P < 0.01) by intervention group for mean BMI (MM: 22.0 (2.4), IFA: 21.6 (2.7); FA:21.4 (2.9)), and the prevalence of underweight (MM: 5.1%, IFA: 10.1%; FA:14.4%), but no differences in overweight (MM: 21.3%, IFA:20.3%; FA:21.3%), or other anthropometric measurements (weight to hip ratio, arm circumference and skinfold thickness). Preconception supplementation with MM resulted in higher BMI and greater reductions in maternal underweight when compared to IFA and FA only. The prevalence of overweight increased dramatically over time but there with no differences by intervention group at 6–7 y PP. These findings suggest that preconception micronutrient interventions may have long term effects on maternal BMI that need to be further examined. The Nestle Foundation, the Mathile Institute, and the Micronutrient Initiative.