Impact of Pre-pregnancy BMI and Gestational Weight Gain on Fetomaternal Outcomes: A Cross-Sectional Analytical Study

Pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) are modifiable determinants of adverse maternal and neonatal outcomes. This study evaluated the association of BMI and GWG, based on 2009 Institute of Medicine (IOM) recommendations, with fetomaternal outcomes in a tertiary care setting.

A prospective cohort study was conducted among 300 singleton pregnant women aged 20-34 years attending a tertiary hospital. Women were categorized by pre-pregnancy BMI (underweight n=90, normal n=120, overweight n=60, obese n=30) and GWG class (appropriate n=146, excess n=56, inadequate n=98). Maternal and neonatal outcomes were compared using chi-square/Fisher's exact tests. A p-value <0.05 was considered statistically significant.

Obese women were predominantly ≥30 years (18; 60%) (p<0.001) and had higher lower-segment caesarean section (LSCS) rates (16; 53.3%) (p<0.001). Post-term delivery was common in overweight and obese groups (36; 60% and 18; 60%) (p<0.0001), while preterm delivery was higher in underweight women (35; 38.9%) (p<0.0001). Delayed wound healing increased with BMI, peaking in obese women (19; 63.3%) (p<0.0001). In GWG analysis, inadequate gain was strongly associated with preterm delivery (72; 73.5%) (p<0.001), whereas excess gain was linked to post-term delivery (36; 64.3%), induction (39; 69.6%), and LSCS (26; 46.4%) (p<0.001). Neonatally, macrosomia was highest in obese (11; 36.7%) and excess GWG (21; 37.5%) groups (p<0.001), while low birth weight was concentrated in inadequate GWG (70; 71.4%) (p<0.001). NICU admissions were highest in obese BMI (18; 60%) and inadequate GWG (68; 69.4%) (p<0.001).

Extremes of BMI and GWG are associated with adverse maternal and neonatal outcomes. Optimizing pre-pregnancy BMI and maintaining appropriate GWG may substantially improve fetomaternal outcomes.