Transition of Biparietal Diameters at Antenatal and Postnatal Periods

The antenatal ultrasonic and postnatal caliper measurements for biparietal diameters were carried out in 44 spontaneous vaginal deliveries (24 primiparas and 20 multiparas) and 12 deliveries by caesarean sections, in an attempt to assess the accuracy of ultrasonic cephalometry and recovery of the fetal moulding. Biparietal diameter determined ultrasonic measurement within 24 hours before labor was smaller than that of neonates by the caliper measurement within one hour after labor, by an average of 1.83mm in cases of caesarean sections, and each biparietal diameter in primiparas, multiparas, and caesarean sections showed a different transition.