(928) Association Between Gestational Weight Gain and Short-term Pregnancy Outcomes

Secondary analysis of a prospective cohort study of nulliparous, singleton pregnancies (2010-2013). Pregnancies > 20 weeks’ were included while those with genetic or structural anomalies or missing outcome data were excluded. The exposure was GWG classified as below, within, or above IOM guidelines. Primary outcomes were composites of maternal and neonatal morbidity and mortality (Table), and secondary outcomes were their individual components. Those above or below recommended GWG were compared with those within IOM guidelines. Rates of outcomes by GWG category are reported. Multivariable modeling estimated the association between GWG and the selected outcomes.

Results: Of 8,997 pregnancies analyzed, 449 (32.2%) were below, 741 (30.5%) were within, and 2,205 (43.2%) were above IOM guidelines. Individuals within guidelines were more likely to have a normal pre-pregnancy body mass index. The overall prevalence of composite maternal morbidity was 38.1% and composite neonatal morbidity was 24.0%. GWG above IOM guidelines was associated with higher maternal morbidity (43.2% vs 30.5%, aOR 1.48 95% CI 1.33-1.65; Table). GWG above IOM guidelines was associated with a lower odds of neonatal morbidity (26.3% vs 27.2%, aOR 0.85, 95% CI 0.76-0.95), with preterm delivery and SGA driving this relationship. GWG below IOM guidelines was associated with higher neonatal morbidity (aOR 1.55, 95% CI 1.34-1.78; Figure).

Conclusion: While there is an association between GWG above IOM guidelines and maternal morbidity, there was an inverse relationship with neonatal morbidity. A better understanding of both short and long-term adverse pregnancy outcomes based on GWG is needed.