Sonographic fetal weight estimation in a south-east Asian population.
OBJECTIVE
To determine the optimal sonographic fetal weight estimation formula for a mixed south-east Asian population near term.


METHODS
Seventy-eight uncomplicated pregnancies were monitored between January 1996 and January 1997. Biparietal diameter, head circumference, abdominal circumference and femur length were measured and the following formulae were tested: Campbell, Shepherds and Hadlock. The estimated fetal weight was calculated by 12 different methods. The weight estimate was then projected forward to the time of delivery using the gestation-adjusted forward projection method. The weight estimation error was derived from the difference between the projected fetal weight and birth weight, and expressed as a percentage of birth weight.


RESULTS
The mean time interval from the time of ultrasound fetal weight estimation to delivery was 4.4 days. The birth weight ranged between 2,330 to 4,215 g. The best performing formula was Hadlock's formula using the head circumference, abdominal circumference and femur, with the perimeters calculated using the ellipse function. The standard deviation of error for this formula was 8.66%.


CONCLUSIONS
Even though the Hadlock formula was originally derived from an American population, it was equally useful in south-east Asian population.
Venkat
A
A
Department of Obstetrics and Gynaecology, Antenatal Diagnostic Centre, National University Hospital, Singapore.
Chinnaiya
A
A
Gopal
M
M
Mongelli
J M
JM
D000328:Adult; D044466:Asian People; D001724:Birth Weight; D005260:Female; D020567:Fetal Weight / Q000208:ethnology*; D006801:Humans; D015588:Observer Variation; D011247:Pregnancy; D016216:Ultrasonography, Prenatal