Preconception micronutrient supplementation affects maternal body mass index and body composition post-partum: A randomized controlled trial in Vietnam.

BACKGROUND: While 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 body mass index (BMI) and composition at 6-7 y post-partum (PP).

METHODS: 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 2800μg folic acid (FA) only, 60mg iron and 2800μg FA (IFA), or multiple micronutrients (MM) (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 6-7 y PP. Body fat was assessed using bioelectric impedance at 6-7 y PP (n=867). Group comparisons were done using ANOVA or chi-square tests and general linear models for adjusted models.

RESULTS: At 6-7 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, IFA:14.0, FA:14.3 kg) and prevalence of underweight based on BMI<18.5 kg/m2 (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 kg/m2 ) or other anthropometric measurements.

CONCLUSIONS: Preconception MM supplementation was associated with lower prevalence of underweight and higher percent fat, when compared to IFA and/or FA only. Preconception micronutrient interventions may have long-term effects on maternal health and merit further examination. The trial was registered at ClinicalTrials.Gov as NCT01665378.