Preconception Micronutrient Supplementation Affects Maternal BMI and Body Composition Postpartum: A Randomized Controlled Trial in Vietnam.

BACKGROUND:Although there is growing evidence on the role of preconception nutrition for birth outcomes, limited evidence exists for its effects on maternal health. OBJECTIVES:This study evaluates the impact of preconception micronutrient supplementation on maternal BMI (kg/m2) and composition at 6 to 7 y postpartum (PP). METHODS:We followed females who participated in a randomized controlled trial of preconception supplementation in Vietnam and delivered live offspring (n = 1599). Females received weekly supplements containing either 2800 μg folic acid (FA) only, 60 mg iron and 2800 μg FA (IFA), or multiple micronutrients (MMs) (15 micronutrients including IFA) from baseline until conception followed by daily prenatal IFA supplements until delivery. Height, weight, mid-upper arm circumference, triceps skinfold, and waist-hip circumference were measured at recruitment and at 1, 2, and 6 to 7 y PP. Body fat was assessed using bioelectric impedance at 6 to 7 y PP (n = 867). Group comparisons were made using analysis of variance or chi-square tests and general linear models for adjusted models. RESULTS:At 6 to 7 y PP, we found significant differences (P < 0.05) by treatment group for mean percent fat (MM: 29.2%; IFA: 27.6%; FA: 27.8%), absolute fat mass (MM: 15.1 kg; IFA: 14.0 kg; FA: 14.3 kg), and prevalence of underweight based on BMI < 18.5 (MM: 5.8%; IFA: 10.3%; FA: 14.3%). Mean BMI and triceps skinfold thickness were higher in the MM group, but these differences were not statistically significant; the differences in absolute fat mass were also attenuated after controlling for body weight. No differences were observed for fat-free mass, prevalence of overweight (BMI >23), or other anthropometric measurements. CONCLUSIONS:Preconception MM supplementation was associated with lower prevalence of underweight and higher percent fat when compared with IFA and/or FA only. Preconception micronutrient interventions may have long-term effects on maternal health and merit further examination. This trial was registered at clinicaltrials.gov as NCT01665378.