Impact of active phase duration on neonatal and maternal adverse outcomes: A systematic analysis of parity stratification, body mass index interaction, and predictive modeling in a retrospective cohort

Prolonged active phase duration independently predicts maternal and neonatal morbidity in nulliparous women, with risk amplification in specific BMI subgroups. Parity stratification and nonlinear modeling enhance individualized labor management. Clinically applicable predictive tools integrating labor progression and maternal characteristics might optimize early intervention, reducing morbidity in modern obstetric practice.