Objectives: To investigate factors associated with the occurrence of transient fetal bradycardia after external cephalic version, and labour outcome after isolated transient fetal bradycardia.
Design: Cohort study.
Setting: Teaching hospital with a policy of offering external cephalic version for breech presentation at or beyond 36 weeks of gestation.
Population: Four hundred and twenty-nine external cephalic versions performed over a 5-year period.
Methods: Between group differences were compared with the unpaired t test or the chi2 test. Logistic regression analysis was performed to exclude confounding effects.
Main outcome measures: Incidence of caesarean section for fetal distress.
Results: Transient fetal bradycardia occurred in 8.4% of external cephalic versions, and was associated with a successful version (OR 16.45, P < 0.001), a difficult procedure (OR 3.70, P = 0.001), and nulliparity (OR 2.83, P = 0.007). The incidence of intrapartum caesarean section for fetal distress was 16.7% in pregnancies with transient fetal bradycardia, compared with 7.9% in those without (OR 2.34, 95% CI 0.81, 6.71).
Conclusions: Transient fetal bradycardia after external cephalic version may be associated with a higher risk of intrapartum caesarean section for fetal distress.