New definitions, old complications: The association between duration of transition from latent to active labor and adverse obstetrical outcomes.

Objective: To explore the relationship between the duration of transition from latent to active labor and various obstetric, maternal, fetal, and neonatal outcomes.

Methods: A retrospective cohort study was conducted on term, singleton deliveries at Soroka University Medical Center from 2013 to 2018. Data were extracted from electronic medical records. The exposure variable was defined as prolonged transition, which was itself defined as the upper 10th centile of dilation duration from 4 to 6 cm. Clinical and demographic characteristics were compared using χ test. Multivariate logistic regression was used to estimate the contribution of a prolonged transition with each adverse outcome adjusting for potential confounders.

Results: In all, 12 104 deliveries met the inclusion criteria. The mean ± standard deviation of duration of dilation from 4 to 6 cm was 03:07:58 ± 03:03:42 (hours:minutes:seconds). Progress curves varied significantly among patients with different obstetrical and demographic characteristics. Prolonged transition was significantly linked to an increased risk of cesarean delivery (adjusted odds raito 2.607, 95% confidence interval 2.171-3.130, area under the curve 0.689) and higher rates of maternal and neonatal morbidity.

Conclusions: Patients experiencing transition phases exceeding the 90th centile faced an elevated risk of cesarean delivery and postpartum complications. Future studies should focus on interventions during the transition phase to improve pregnancy outcomes and enhance patient safety.