Association of Prepregnancy Body Mass Index with Gut Microbiota Diversity and Abundance in Pregnant Women

Background: Understanding the link between prepregnancy nutritional status and gut microbiota during pregnancy may lead to novel maternal and child health interventions. Objective: To explore the association of prepregnancy body mass index (BMI) status with gut microbiota diversity and abundance during pregnancy. Methods: A cross-sectional study was conducted on 90 pregnant women from primary health centers in Jakarta, Indonesia. Trained staff interviewed women on sociodemographic characteristics and nutrient intake, gathered data on prepregnancy BMI from antenatal records, and obtained fecal samples. Samples were analyzed for microbiota diversity indices [Shannon, Faith phylogenetic diversity (Faith PD), and Chao1] and abundance using 16S ribosome ribonucleic acid sequencing. Multivariate logistic regression was performed adjusting for carbohydrate and protein intake, ethnicity, and education to determine the relationship between prepregnancy BMI and the alpha diversity indices and the presence of the phylum Firmicutes and genera Prevotella and Blautia. Results: Pregnant women who were overweight or obese (BMI ≥23.0 kg/m²) before pregnancy had significantly lower odds of having gut microbiota diversity above the median of the Shannon index [adjusted odds ratio (aOR): 0.37, 95% confidence interval (CI): 0.14, 0.97, P = 0.042], Faith PD (aOR: 0.23, 95% CI: 0.07, 0.75, P = 0.015), and Chao1 (aOR: 0.25, 95% CI: 0.09, 0.67, P = 0.006) compared with those who were neither overweight nor obese. Prepregnant women who were overweight or obese also had significantly lower odds of having levels above the median of the phylum Firmicutes (aOR: 0.38, 95% CI: 0.15, 0.98, P = 0.045) and genus Blautia (aOR: 0.32, 95% CI: 0.12, 0.85, P = 0.022) compared with women who were neither overweight nor obese. Conclusions: Prepregnancy overweight or obese status was associated with lower gut microbiota diversity and lower abundance of Firmicutes and Blautia among pregnant women in an urban community. These findings suggest that prepregnancy interventions to control BMI may improve gut flora and potentially benefit pregnant women.