OBJECTIVE

To determine the association between maternal obesity and delivery due to chorioamnionitis prior to labor onset, among expectantly managed women with preterm premature rupture of membranes (pPROM).

METHODS

This was a secondary analysis of a multicenter randomized trial of magnesium sulfate versus placebo to prevent cerebral palsy or death among offspring of women with anticipated delivery at 24-31-week gestation. After univariable analysis, Cox proportional hazard evaluated the association between maternal obesity and chorioamnionitis, while Laplace regression investigated how obesity affects the gestational age at delivery of the first 20% of women developing the outcome of interest.

RESULTS

A total of 164 of the 1942 women with pPROM developed chorioamnionitis prior to labor onset. Obese women had a 60% increased hazard of developing such complication (adjusted HR 1.6, 95%CI 1.1-2.1, p = .008), prompting delivery 1.5 weeks earlier, as the 20th survival percentile was 27.2-week gestation (95%CI 26-28.6) among obese as opposed to 28.8 weeks (95%CI 27.4-30.1) (p = .002) among nonobese women.

CONCLUSIONS

Maternal obesity is a risk factor for chorioamnionitis prior to labor onset. Future studies will determine if obesity is important enough to change the management of latency after pPROM according to maternal BMI.