Pelvic minus fetal diameter: value of pelvimetry in the detection of cephalopelvic disproportion

Cephalopelvic disproportion between pelvic and fetal diameters has been evaluated by pelvimetry. The study consisted of 257 women with pelvimetry by digital-image-intensifier radiography and fetometry by US. Information about the management of labour and the mode of delivery has been obtained from the obsterician. Differences between five pelvimetric diameters and the fetal biparietal diameter (BIP) have been correlated to the mode of delivery. Kruskal-Wallis and Mann-Whitney U-tests show high significance for small or negative differences between interspinous as well as intertuberous distance and BIP in the group of Caesarean sections. According to empirical determination cephalopelvic disproportion can be supposed for differences 0.0 cm and borderline conditions for 0.0–1.0 cm. The investigated sagittal pelvic diameters did not show a correlation to the mode of delivery. For the detection of cephalopelvic disproportion interspinous distance-BIP is suited best. In conclusion, the plane of the mid-pelvis has been found to be the most important parameter. Correspondence to: K. J. Lehmann