Risk of Preterm Birth among Secundiparas with a Previous Cesarean due to a Failed Vacuum Delivery

Background: Studies have found an association between second-stage cesarean sections (SSCSs) and subsequent preterm birth (PTB). We aimed to evaluate if secundiparas with previous second-stage cesarean sections due to a failed vacuum delivery (SSCS-F-VD) are associated with PTB in the subsequent delivery compared with secundiparas with previous spontaneous vaginal birth (SVB) at term. A secondary aim was to compare this association with secundiparas with a previous SSCS at term. Methods: A historical, prospective, longitudinal cohort study was conducted in a large tertiary university hospital between 2006 and 2019. Matched mothers who experienced first and second births at the indexed hospital, excluding those with a previous miscarriage or multiple pregnancy in either the first or second birth were grouped based on the mode of delivery and gestational week of the first birth. Results: Parturients with term SVB and term SSCSs were less likely to experience PTB in the following delivery compared with those who underwent an SSCS-F-VD, with 496/14,551 (3.4%) versus 6/160 (3.8%) versus 5/61 (8.2%), respectively, at p < 0.001. A logistic regression model revealed that secundiparas with previous SSCS-F-VD had an association with PTB in the following delivery compared with term SVB, with an OR of 2.756 (1.097; 6.922, p = 0.031). Conclusion: Previous SSCS-F-VD is associated with PTB in the following delivery, offering valuable insights for pregnancy management and patient counseling.