Head circumference has advantage over biparietal diameter, as the head circumference tends to remain constant even when head shape and cephalic index change. Abdominal circumference correlates with fetal weight.
Limitations: Abdominal circumference can be difficult to measure accurately by ultrasound.
Hadlock (1984)
estimated fetal weight in grams =
=10^(1.182 + (0.0273 * (head circumference in cm) + (0.07057 * (abdominal circumference in cm)) - (0.00063 * ((abdominal circumference in cm)^2)) - (0.0002184 * (abdominal circumference in cm) * (head circumference in cm)))
Jordaan (1983)
estimated fetal weight in grams =
=10^(0.9119 + (0.0488 * (head circumference in cm)) + (0.0824 * (abdominal circumference in cm)) - (0.001599 * (abdominal circumference in cm) * (head circumference in cm)))
Weiner (1985)
estimated fetal weight in grams =
= (-2134.616) + (94.593 * (head circumference in cm)) + (34.227 * (abdominal circumference in cm))
Weiner (1985)
estimated fetal weight in grams =
=10^(1.6575 + (0.04035 * (head circumference in cm)) + (0.01285 * (abdominal circumference in cm)))
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