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Is the technique and time taken for vaginal breech delivery important for optimal perinatal outcome?

Sir, Despite evidence from the ‘Term Breech Trial’, vaginal breech deliveries continue to occur, and it is generally accepted that the proper technique of delivery is important for optimal perinatal outcome. Since ‘assisted breech delivery’ in carefully selected cases became accepted practice from the 1960s onwards, birth asphyxia rather than fetal trauma has accounted for the vast majority of perinatal deaths. It is reasonable to assume that birth asphyxia may be related to the time taken to complete breech delivery. This is because cord compression is almost invariable after partial expulsion of the fetus. William’s Textbook of Obstetrics, for example, states ‘The anterior hip delivers followed by external rotation to sacrum anterior position. The mother should be encouraged to continue to push, as the cord is now drawn well down into the birth canal and is being compressed with resultant fetal bradycardia’. The cord can be compressed at several levels between the fetal body and the pelvic brim, pelvic floor or introitus. Moreover, cord pulsations on the fetal side may represent only a fetal heart beat rather than fetoplacental blood flow. It is rarely possible to continue obtaining fetal heart rate trace (CTG) at this stage. In ‘Principles of Obstetrics’ Brian Hibbard states, ‘Usually with the next contraction the trunk will be born up to the umbilicus. The umbilical cord may be under tension and a loop of cord should be drawn down. From this time onward it must be assumed that there is no further effective placental blood flow. Pulsation of the umbilical cord is not an indication that the cord is not obstructed. Therefore, it is important that delivery is progressive and that the infant is delivered within 7–8 minutes from this time. An assistant should note the time and inform the obstetrician as each minute passes’. After 8–10 minutes of significant cord compression there is likely to be asphyxial brain injury or death. Because the fetal pH may already be low at the start of breech delivery, a recommendation of 5 minutes may be more appropriate. Even though 6 out of 16 perinatal deaths in the ‘Term Breech Trial’ were attributed to difficult vaginal delivery, the time taken for delivery was not recorded and it is not possible to infer if time taken for delivery had any influence on perinatal morbidity. The dictum ‘Hands off the breech’ should mean hands off the buttocks, but not minimal intervention even after spontaneous delivery up to the umbilicus. The expert consensus group for the ‘Term Breech Trial’ recommended minimal intervention (apart from controlling delivery of head) and avoidance of even gentle traction on fetal trunk without any evidence base. This is in contrast to most obstetric textbooks written by authors with substantial practical experience of breech deliveries. Although it is important to avoid fetal trauma, it is even more important to avoid fetal asphyxia by highlighting the significance of time taken for delivery of breech baby and record this important data in clinical records and future trials. It is not possible to be dogmatic about the optimal time frame for conduct of breech delivery, but it seems reasonable to aim to complete the delivery in 5 minutes so that spare time is available when difficulties arise.