Impact of intrapartal ultrasound to assess fetal head position and station on the type of obstetrical interventions at full cervical dilatation.

Objectives: Recent ultrasound studies have shown that it is feasible to objectively and reproducibly assess fetal head position and station within the pelvis. We sought to evaluate the impact of this new approach on decision making by physicians in a cohort of women with a prolonged second stage of labor.
Methods: This was a retrospective cohort study that included all women with fetuses in cephalic presentation, who were diagnosed with a prolonged second stage of labor, and who delivered in a 1-year period. We compared a group of women (n = 121) with a prolonged second stage of labor who underwent intrapartal ultrasound prior to obstetrical intervention (Group A, n = 43) with a group of women for whom the delivery modus was decided upon after clinical digital examination alone (Group B, n = 78).
Results: There were no significant differences in maternal and neonatal morbidity between both groups. The rate of second-stage cesarean section was significantly higher (p < 0.50) in Group B without ultrasound compared to Group A with ultrasound prior to operative delivery (20/78 vs. 7/43). Seven patients in Group A delivered spontaneously, but none of the patients in Group B had spontaneous deliveries.
Conclusions: Intrapartal ultrasound in patients with a prolonged second stage of labor may change obstetrical practice by reducing the number of second stage cesarean section without increasing maternal and neonatal morbidity.