Breech presentation in South Australia, 1987-1989.

This study compares the maternal, obstetrical, labour and pregnancy outcome characteristics of 2,412 breech-presenting births with 17,946 vertex-presenting births. Mothers of babies presenting as breeches were significantly more likely to have had a previous miscarriage, an obstetric complication, a threatened miscarriage or threatened labour during the current pregnancy, or Caesarean section than mothers of babies with vertex presentation. The babies presenting as breeches had significantly more neonatal morbidity and perinatal mortality. They showed higher rates of suspected intrauterine growth retardation, prematurity, low birth-weight, low Apgar scores and congenital anomalies. The overall perinatal mortality for breech presentations was almost 9 times higher than for vertex presentations. Unconditional multiple logistic regression analysis showed that, even after adjusting for low birth-weight and the presence of congenital anomalies, breech presentation still showed a statistically significant association with perinatal death. The study alludes to the possibility that breech presentation, in a significant number of cases, may not be coincidental but a marker for some preconceptional or prenatal disturbance. The study also shows an excess of breech presentations in females which is unexplained and may point to a genetic or hormonal susceptibility of the fetus.