The impact of excessive gestational weight gain timing on neonatal outcomes in women with class III obesity.

Objective: This study evaluated the influence of early gestational weight gain (GWG) on neonatal outcomes among women with class III obesity.

Study Design: Retrospective cohort of women with class III obesity who gained more than the Institute of Medicine (IOM) guidelines (>20lbs). Women gaining ≥75% of total gestational weight prior to 28 weeks (EWG) were compared to women gaining <75% of their total weight prior to 28 weeks (SWG). The primary outcome was a neonatal composite morbidity and mortality. Secondary outcomes included individual components of composite and LGA.

Results: Of 144 women identified, 42 (29.2%) had EWG and 102 (70.8%) had SWG. Though 11% of the total population had composite neonatal morbidity, this did not differ between groups ( = .4). LGA was nearly twice as common in the SWG group (41% vs 26%,  = .13). EWG was associated with decreased risk of LGA (AOR 0.25 95% CI 0.08, 0.78) and lower median birth weight (AOR -312 g 95% CI -534.7, -90.2).

Conclusion: Though adverse neonatal outcomes were common in this population, timing of gestational weight gain was not correlated. Increased rates of LGA and higher median birth weight in the SWG group suggests excessive GWG continuing in the third trimester of pregnancy may be of import for neonatal size.