COMBINATION OF ULTRASOUND PELVIMETRY AND FETAL SONOGRAPHY IN PREDICTING CEPHALOPELVIC DISPROPORTION

Objective To assess a method of antepartum diagnosis of cephalopelvic disproportion by comparing the diameters of fetal head with those of t he maternal midpelvis. Methods Transvaginal ultrasound pelvimetry was per formed on 190 healthy primigravidas with cephalic presentation at 28-35 weeks of gestation, and the fetal heads were measured within one week before delivery. The cephalopelvic indices of diameter, circumfe rence and area were calculated and compared. Results The index exhibit ing the highest degree of accuracy (77.9%) was the cephalopelvic index of diameter (CID) defined as the difference between the mean diameter of the midpelvis and the fetal biparietal diameter (BPD). Eighty-thre e percent of the cases with CID less than 15.8 mm needed operative del ivery, and 76.2% of the cases with CID more than 15.8 mm underwent vag inal delivery. Conclusions The CID may be used to identify cephalopelv ic disproportion before the labor and help obstetricians choose the mo st appropriate form of delivery in an uncomplicated vertex presentatio n.