Rotational forceps versus manual rotation and direct forceps: A retrospective cohort study

Rotational forceps and manual rotation followed by direct forceps are techniques used in the management of malposition of the fetal head in the second stage of labor. However, there is widespread debate regarding their relative safety and utility. We aimed to compare the effectiveness and safety of rotational forceps with manual rotation followed by direct forceps, for management of fetal malposition at full dilation.

A retrospective cohort study in a single tertiary obstetric unit with >6000 births per year. We recorded and analysed outcomes of 104 sequential rotational forceps births over 21 months (Jan 2010-Sept 2012) and 208 matched chronologically sequential attempted manual rotations and direct forceps births (1:2 by number). Univariable and multivariable approaches used for statistical analysis. The main outcome measure was vaginal birth.

The rate of vaginal birth was significantly higher with rotational forceps than with manual rotation followed by direct forceps (88.5% vs 82.2%, RR 1.17, 95% CI 1.04-1.31, p=0.017). Births by rotational forceps were associated with a significantly higher rate of shoulder dystocia (19.2% vs 10.6%, RR 2.35, 95% CI 1.23-4.47, p=0.012), but not of neonatal injury. There were no significant differences in all other maternal and neonatal outcomes between the two modes of birth.

The use of rotational forceps was associated with a statistically significantly higher rate of vaginal birth, but also of shoulder dystocia, compared to manual rotation followed by direct forceps. This is the first study to demonstrate a statistically significant increase in the rate of shoulder dystocia following rotational forceps birth.