Limitations: Abdominal circumference can be difficult to measure accurately by ultrasound.
Hadlock (1984)
estimated fetal weight in grams =
=10^(1.5662 - (0.0108 * (head circumference in cm)) + (0.00034 * ((head circumference in cm)^2)) + (0.0468 * (abdominal circumference in cm)) + (0.171 * (femoral diaphysis length in cm)) - (0.003685 * (abdominal circumference in cm) * (femoral diaphysis length in cm)))
Hadlock (1985)
estimated fetal weight in grams =
=10 ^ (1.326 + (0.0107 * (head circumference in cm)) + (0.0438 * (abdominal circumference in cm)) + (0.158 * (femoral diaphysis length in cm)) - (0.00326 * (abdominal circumference in cm) * (femoral diaphysis length in cm)))
Ott (1986)
estimated fetal weight in kilograms =
=10 ^ (-2.0661 + (0.04355 * (head circumference in cm)) + (0.05394 * (abdominal circumference in cm)) + (1.2594 * (femoral diaphysis length in cm) / (abdominal circumference in cm)) - (0.0008582 * (abdominal circumference in cm) * (head circumference in cm)))
where:
• The ratio of femur length to abdominal circumference reflects accurately fetal growth patterns.
• In the presence of oligohydramnios an additional 2.88% of the calculated body weight is added to the estimate, to compensate for a tendency to underestimate body weight.
Vintzileos (1986)
estimated fetal weight in grams =
=10 ^ (2.082 + (0.0018 * (abdominal circumference in cm)) + (0.004 * (femoral diaphysis length in cm) * (head circumference in cm)) - (0.00000001509 * (((femoral diaphysis length in cm) * (head circumference in cm)) ^ 3)))
Weiner (1985)
estimated fetal weight in grams =
=10 ^ (1.6961 + (0.02253 * (head circumference in cm)) + (0.01645 * (abdominal circumference in cm)) + (0.06439 * (femoral diaphysis length in cm)))
