Ultrasonographic biometry: Biparietal Diameter of Nigerian foetuses

BACKGROUND: Foetal biparietal diameter has been studied previously in Nigerian foetuses but populations have been too small to make categorical conclusions regarding the reference values/data. MATERIALS AND METHODS: In a cross sectional study, the foetal biparietal diameter (BPD) of 13,740 foetuses in Jos were measured with grey ultrasound machine in 13,740 Nigerian women during normal pregnancy and the mean BPD values for each week of pregnancy between 12 and 42 weeks were determined. RESULTS: The mean biparietal diameter value was 29.4mm at 14 weeks, 49.4mm at 20 weeks, 78.4mm at 30 weeks, 91.5 at 37 weeks and 95.6mm at 40 weeks. There was a positive relationship between gestational age and biparietal diameter with correlation coefficient of R(2) = 0.9996 (P < 0.001), and with fetal weight. The increase in BPD with increasing age in the study population showed a curve similar to that of Europeans. CONCLUSIONS: Ultrasonographic measurement of biparietal diameter in Nigerian fetuses showed a linear correlation exists between BPD and gestational age, as well as BPD and foetal weight in normal foetuses.