Objective: In the context of a medical termination of pregnancy, prolonged labor may accentuate the difficulty of women’s experience and increase the risk of associated complications. The factors associated with prolonged labor are not known. Reducing the duration of labor could limit these complications.Determining the relevant factors associated with prolonged labor defined as a delay between the onset of induction and delivery greater than or equal to 12 hours and comparing the complications rates between the two groups.
Method: We conducted a retrospective study at Port Royal Maternity Hospital from 2017 to 2019, including medical terminations of pregnancy by vaginal delivery in the 2nd and 3rd trimesters for fetal or maternal reasons.
Results: Two hundred twenty-seven patients were included and divided into two comparative groups based on the duration of labor: labor <12h (N= 173) and labor ≥12h (N=54). The mean maternal age was 33.7 years. Forty-four percent of patients were nulliparous, 15.8% had a history of cesarean section. The average gestational age was 20+2 weeks of gestation. The average duration of labor was 9.7 hours. The duration of labor was greater than 24 hours in 3% of cases (7/227). Advanced gestational age (22+3 vs 20+5 p=0,04) and nulliparity (p=0.01) were associated with prolonged labor. Two other intermediate factors, not independent of the duration of labor, were significant: long time to rupture of membranes (239 min vs 427 min p<0,01) and an unfavorable Bishop score at rupture (p=0,003). In both groups, the complications were placental retention and the occurrence of fever during labor.
Conclusion: Two main factors affecting labor duration were identified in this study (term and nulliparity). This knowledge could allow women to be better informed about the expected time of labor and the potential associated risks.