Neonatal outcomes of two-step delivery in low-risk pregnancy: A prospective observational study

Extraction of the fetal body is typically performed immediately after delivery of the head in Western obstetric care. Reports justifying immediate extraction are few. Two-step delivery entails waiting for the next uterine contraction after delivery of the head. The present study evaluates neonatal asphyxia and respiratory impairment in two-step delivery using the head-to-body delivery interval.

This prospective observational study performed at a single birth clinic used the data of 262 low-risk pregnant women with two-step delivery. We measured the time interval of head-to-body delivery and correlation analysis and simple linear regression analysis between the head-to-body delivery interval and umbilical artery pH. The women were divided into two groups according to the head-to-body delivery interval: ≤60 or >60 s. The prevalence of neonatal asphyxia and neonatal respiratory impairment was compared between the groups.

The mean head-to-body delivery interval was 88.9 ± 71.3 s. The umbilical artery pH tended to decrease with increasing head-to-body delivery interval; however, there was almost no correlation and the decline of pH was only 0.010 for every additional minute. Low Apgar score incidence at 5 min did not differ significantly between the groups. No cases of shoulder dystocia were reported, and tachypnea at 4 h after birth occurred in 3% of the births.

A longer head-to-body delivery interval is not associated with negative outcomes in two-step delivery. We believe that two-step delivery could have some superior outcomes compared with one-step delivery outcomes, particularly as to improving fetal circulation and preventing shoulder dystocia.