Pelvimetry assesses the size of a woman's pelvis by clinical examination, or by conventional X-rays, computerised tomography scanning, or magnetic resonance imaging.The objective of this review was to assess the effects of pelvimetry (performed antenatally, intrapartum or postpartum) on the method of delivery, and on perinatal mortality and morbidity, and on maternal morbidity.The Cochrane Pregnancy and Childbirth Group trials register was searched.Acceptably randomised comparisons of the use of pelvimetry in cephalic presentations.Trial quality was assessed and data were extracted by one author.Four trials of over 1000 women were included. The trials were generally not of good quality. Women undergoing pelvimetry were more likely to be delivered by caesarean section (odds ratio 2.17, 95% confidence interval 1.63 to 2.88). No significant impact was detected on perinatal outcome.There is not enough evidence to support the use of X-ray pelvimetry in women whose fetuses have a cephalic presentation.