Outcomes of attempted vaginal births after previous recurrent operative vaginal deliveries: An individual cumulative risk analysis

Background: Data about the risk of recurrence of vacuum extraction (VE) in multiple consecutive deliveries are scarce. We aimed to evaluate the pattern and individual cumulative risk of recurrence of VE in consecutive term deliveries.

Study design: A retrospective cohort study based on a validated electronic database at a single center between 2005 and 2019. For the purpose of the study, we focused on consecutive term deliveries of all primiparas (P1) that had a record of at least one additional delivery during the study period. We identified P1 VE deliveries (reference group) and calculated the individual cumulative risk of repeated VE for three consecutive deliveries. Multivariate analysis was conducted adjusting for potential confounders.

Results: We identified 35 113 primiparas that met inclusion criteria. The overall VE rate for P1 was 17.9% (6969 parturient). The cumulative rates of repeated VEs at the 2nd, 3rd, and 4th deliveries were 8.6%, 26.8%, and 25.0%, respectively. The risk of recurrent VE for each of the consecutive deliveries was confirmed after adjustment for confounders (aOR [95% CI]: 5.8 [4.76-7.04], 34.2 [18.59-62.81], and 113.9 [9.77-1328.69] for the 2nd, 3rd, and 4th consecutive deliveries, respectively).

Conclusion: Women with VE at the first and second deliveries have a substantially increased risk of VE in their following deliveries; this finding may influence woman's preference when choosing future mode of delivery.