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CME Credit Offered
CME Credit Offered
Abstract Award
Abstract Award
Recording available 2/16-5/2
Recording available 2/16-5/2
AIUM Credit
AIUM Credit
Foundation Awardee
Foundation Awardee
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Abstract Award
Abstract Award
Foundation Awardee
Foundation Awardee

Poster Session 2

Category: Epidemiology

Poster Session 2

(675) Change in interpregnancy BMI and perinatal outcomes among overweight individuals during their first pregnancy

Wednesday, February 11, 2026
3:30 PM - 5:00 PM  
Objective:
As with the general U.S. population, BMI and obesity rates have risen among women of reproductive age. While it is understood that maternal overweight and obesity are associated with adverse perinatal outcomes, less data focus on the impact of interpregnancy BMI changes on subsequent pregnancies. This study compares the clinical outcomes of second pregnancies among women classified as overweight in their first pregnancy, examining differences between those who increased or decreased their BMI category and those who remained in the overweight category.

Study Design:
This retrospective cohort study used linked birth certificate-hospital discharge data for births in California between 2008-2020. We included two consecutive singleton, non-anomalous births between 23-42 weeks’ gestation and required an overweight BMI category for the first pregnancy. We used chi-square tests and multivariable Poisson regression models for adverse perinatal outcomes and adjusted risk ratios (aRR) were estimated.

Results:
A total of 200,297 pregnancies met inclusion criteria. Of these cases, 53.1% remained in the same BMI category, 15.2% reduced BMI category, and 31.7%increased BMI category between pregnancies (Table 1). On multivariate regression, increased interpregnancy BMI was associated with increased risk of gestational diabetes (aRR=1.39, 95% CI 1.35, 1.42), recurrent preeclampsia (aRR =1.41, 95% CI 1.35, 1.47), cesarean delivery (aRR=1.14, 95% CI 1.13, 1.16), postpartum hemorrhage (aRR=1.09, 95% CI 1.03, 1.15), neonatal hypoglycemia (aRR=1.15, 95% CI 1.07, 1.24) and large for gestational age newborns (aRR=1.20 95% CI 1.18, 1.23). An increased interpregnancy BMI was also associated with a decreased risk of placental abruption (aRR=0.85, CI 0.76, 0.94).

Conclusion:
Changes in interpregnancy BMI are associated with differences in perinatal outcomes, with increases in BMI generally linked to worse outcomes. Further research is needed to understand these associations and guide weight management between pregnancies to reduce adverse outcomes.