The influence of maternal height, obstetrical conjugate and fetal birth-weight in the management of patients with breech presentation.

The value of erect lateral X-ray pelvimetry for selecting patients for a safe trial of vaginal delivery was assessed in a retrospective study of 424 women with a breech presentation. A trial labour was more often allowed in women with larger inlet conjugate measurements and the chance of successful vaginal delivery was better with larger pelvic measurements. However, there was no absolute level of pelvic contraction below which vaginal delivery was impossible. The size of the fetus did not determine the rate of planned elective Caesarean section. A fetus weighing greater than 3,500 g, had less than 50% chance of vaginal delivery. It is suggested that antenatal assessment of fetal size should be considered in patients with breech presentation before deciding on the mode of delivery.