Fetal malpresentation following mechanical labor induction

Abstract

Objective To evaluate whether the risk of fetal malpresentation following mechanical labor induction could be accurately predicted. Methods A retrospective study, including all individuals who underwent labor induction at a single tertiary medical center between March 2011 and May 2021. Cohorts of pharmacological (n = 16 480) and mechanical labor induction (n = 6864) were compared, determining malpresentation rate following induction. Individuals with and without fetal malpresentation following balloon placement were compared. Results Malpresentation following balloon placement occurred in 62 patients (0.9%). Those patients with malpresentation following balloon placement were older, had higher body mass index during labor, higher parity, polyhydramnios, higher fetal station at the start of labor induction, and delivered at an earlier gestational age compared with control patients. The combined presence of at least three of these risk factors was associated with a malpresentation rate of 8% (7/88) and yielded a positive likelihood ratio of 9.48 (95% confidence interval [CI] 4.57–19.7). A prediction model using these variables was not sufficiently accurate to predict the risk of malpresentation following balloon labor induction; a calculated area under the generated receiver operating characteristic curve was 0.78 (95% CI 0.72–0.84). Conclusion Several risk factors were identified for malpresentation following mechanical labor induction, although these were of low predictive value.