Assessment of fetal biparietal diameter during normal pregnancy by ultrasound in Nigerian women.

The fetal biparietal diameter (BPD) was measured on 1104 occasions in 552 Nigerian women during normal pregnancy, and the range of BPD values for each week of pregnancy between 12 and 40 weeks was determined. Growth of the BPD in our population showed an asymptotic curve like that of Europeans but our values were slightly higher. The mean weekly increase in the BPD between 13 and 30 weeks gestation was 4.9 mm/week, between 30 and 36 weeks, 3.3 mm/week and between 37 and 40 weeks, 1.7 mm/week. But there was no significant difference between the BPD measurements of Europeans and Nigerian fetuses except towards term.