Estimation of gestational age using trans-cerebellar diameter: a sonographic study of a cohort of healthy pregnant women of Igbo ethnic origin in a suburb of Lagos, southwest Nigeria.

Aim: To use a sonographic method to determine the usefulness of trans-cerebellar diameter (TCD) as an independent estimator of gestational age (GA).

Methods: A convenience sample of 257 healthy pregnant women of Igbo ethnic origin with singleton normal pregnancy whose GA ranged from 16 to 40 weeks were examined. GA was calculated from the date of onset of the last menstrual period (LMP) and was used as the standard criterion, while the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were used to estimate GA.