Risk factors for preterm birth in pregnancies following bariatric surgery: an analysis of the Longitudinal Assessment of Bariatric Surgery-2.

BACKGROUND

Bariatric surgery has been shown to increase the risk for preterm birth in a subsequent pregnancy. Determining factors that contribute to this heightened risk will inform the development of targeted interventions to improve birth outcomes postbariatric surgery.

OBJECTIVES

This study aimed to identify risk factors of preterm birth in pregnancies following bariatric surgery. Factors being considered were preoperative medical conditions and behaviors (e.g., obesity-associated co-morbidities, gastrointestinal symptoms, substance use), antenatal factors (e.g., prepregnancy body mass index, gestational weight gain), and surgery-specific factors (e.g., surgery type, surgery-to-conception interval).

SETTING

Bariatric surgery centers in the United States.

METHODS

This is a retrospective analysis of the Longitudinal Assessment of Bariatric Surgery-2. Participants were women who reported at least 1 singleton live birth during the 7-year postoperative period. Logistic regressions were used to identify risk factors of preterm birth, adjusting for covariates such as maternal age, race, and ethnicity.

RESULTS

Participants (n = 97) were mostly White (84.5%) and non-Hispanic (88.7%). At the time of surgery, the mean age was 29.4 ± 4.6 years, and the mean body mass index was 47.6 ± 6.3 kg/m2. The prevalence of preterm birth was 13.4%. Preoperative gastrointestinal symptoms significantly increased (odds ratio: 1.12; 95% confidence interval: 1.00-1.26), while unexpectedly, excessive versus adequate gestational weight gain (odds ratio: .12; 95% confidence interval: .02-1.00) decreased the odds of preterm birth following bariatric surgery.

CONCLUSIONS

This analysis identified potential risk and protective factors of preterm birth among pregnancies postbariatric surgery. However, given the small sample size, findings should be regarded as hypothesis-generating and merit further study.