786: Prior prolonged first stage of labor is associated with prolonged first stage in subsequent pregnancies


      Limited data exists regarding the impact of a history of a prior prolonged first stage of labor (PPFSL) on labor curves in subsequent pregnancies. We hypothesized that patients with PPFSL were more likely to have an abnormal labor curve in subsequent pregnancies, and ultimately have a higher cesarean section rate. The aim of this study was to explore if a PPFSL is associated with prolonged labor in subsequent pregnancies.

      Study Design

      This was a retrospective cohort study of all women with two consecutive singleton term pregnancies that reached 10 cm cervical dilation in the first pregnancy (regardless of mode of delivery), at tertiary care center from 2004 to 2014. Labor curves and pregnancy outcomes were compared between patients with and without a history with a PPFSL (greater than 12 hours). T-tests & Mann Whitney U tests were used for continuous variables and chi- square/Fisher’s exact tests for categorical variables. Interval-censored regression was used to estimate median times for cervical change.


      2,150 patients had at least two pregnancies during the study, and 204 (9.5%) had a PPFSL. Besides women with a PPFSL to be less likely to have interpregnancy interval (IPI) less than 6 months or an IPI less than 12 months, the groups were similar, with similar rates of spontaneous labor and no significant difference in mode of delivery. Patients with PPFSL were more likely to have another prolonged first stage (OR 2.06, 95%CI 1.35-3.13). There was no difference in the second stage. Patients with PPFSL had significantly longer first stage in the current pregnancy, including a longer time to dilate from 4 to 10 cm (median 5.25 vs 4.01 hrs, p=.01).


      A PPFSL in a previous term pregnancy was associated with a prolonged first stage in a subsequent pregnancy, but was not predictive of a prolonged second stage. However, even with the increased risk of a prolonged subsequent first stage, there was no association with an elevated risk of cesarean or operative delivery. This suggests that natural history of the first stage of labor may be longer in some women, but that may not preclude a vaginal delivery.
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