Perinatal outcome and risk factors of precipitate labor in term primipara: an analysis of 381 cases.

Objective: To investigate the perinatal outcome and risk factors of precipitate labor in term primipara.

Methods: A total of 6951 full-term singleton primiparas with cephalic vaginal delivery in Women's Hospital, Zhejiang University School of Medicine from January 2020 to December 2020 were enrolled, among whom 381 cases of precipitate labor were classified as the precipitate labor group and 762 cases of normal labor were randomly selected as the control group. The perinatal outcomes of the two groups were compared, and the risk factors of precipitate labor were analyzed by multivariate logistic regression.

Results: The incidence of precipitate labor in full-term, singleton pregnancy and cephalic primiparas was 5.48% (381/6951). The durations of the first and second stages of labor in the precipitate labor group were significantly shorter than that in the control group ( <0.01); while there was no significant difference in the duration of the third stage of labor between the two groups ( >0.05). Compared with the control group, the incidence of soft birth canal laceration in the precipitate labor group was increased ( <0.01). However, there was no significant difference in postpartum hemorrhage and neonatal related perinatal outcomes between the two groups (all >0.05). Multivariate logistic regression analysis showed that maternal height ( =1.038, 95% : 1.010-1.067, <0.01), gestational age at delivery ( =0.716, 95% : 0.618-0.829, <0.01), late miscarriage ( =1.986, 95% : 1.065-3.702, <0.05), membrane rupture before labor ( =1.802, 95% : 1.350-2.406, <0.01), labor induction by transcervical balloon ( =3.230, 95% : 2.027-5.147, <0.01), labor induction by propess ( =2.332, 95% 1.632-3.334, <0.01) and labor induction by oxytocin ( =0.291, 95% : 0.219-0.386, <0.01) were independently associated with precipitate labor.

Conclusions: The incidence of precipitate labor in full-term, singleton pregnancy was not low. Precipitate labor could lead to a significant increase in perineal laceration. Maternal height, history of late miscarriage, membrane rupture before labor and labor induction by transcervical balloon, labor induction by propess are risk factors, while labor induction by oxytocin and late gestational time of delivery are protective factors for precipitate labor in term primipara.