Induction of labor in breech-presenting fetuses.

Abstract

We would like to thank Schroll and Krebs for their comments on our manuscript.1 Delivery mode in breech-presenting fetuses will continue to be discussed. An expert group from the Norwegian Center of Medical Method Evaluation reviewed the literature in 2003 and concluded that vaginal delivery could be advised provided there is a qualified selection, careful birth monitoring and the presence of qualified personnel.2 We presented results from a large Norwegian hospital in 2012-2019 and we do agree that 11% of newborns with 5-minute Apgar score <7 in women with planned vaginal birth is a high frequency. The duration of the expulsive phase is longer in vaginal breech deliveries than in cephalic presenting fetuses. It is recommended that the birth attendant should maintain a hands-off position until the fetal umbilicus is visible and then deliver the baby with active maneuvers.3 Planned vaginal breech birth implies an increased risk of short-term fetal morbidity, low 5-minute Apgar score, and a low umbilical arterial pH compared with planned cesarean section.4 We observed 5-minute pH <7.05 in 3.9% of planned vaginal births but metabolic acidosis in only three newborns (0.6%).5 This means that the majority with low pH had a respiratory acidosis with a low risk of long-term adverse outcome. The association between induced cephalic presentations and cesarean sections is discussed. In register-based studies, the frequency of cesarean sections is higher in induced labors, but this is not confirmed in randomized studies, probably due to confounding by indications.6 We did a power analysis before investigating our population and supposed intrapartum cesarean section rates would be 30% in spontaneous labors vs 45% in induced labors. The actual figures were 46% and 48%, respectively, and the difference was not significant after adjusting for confounders. The most important newborn outcome is the frequency of metabolic acidosis, which occurred in only one of 127 newborns among induced labors and in two of 479 in spontaneous labors.5 Our objective was not to discuss whether vaginal breech deliveries still should be recommended, but to compare spontaneous and induced breech deliveries. We think that induction of labor is an acceptable procedure in labor wards practicing vaginal breech deliveries. This is in accordance with recommendations in the recently published NFOG textbook for medical students, which states that spontaneous onset of labor is optimal, but induction of labor for selected patients may be feasible.3