A prospective study was carried out on 50 patients who had their fetal weight estimated by 3 clinicians of different seniority and compared to the ultrasound estimated fetal weights using 3 different formulas. All the patients delivered within 24 hours of their clinical and ultrasound estimates. A wide range of birth-weights (1,800-4,500 g) was estimated among the 3 different races (Malay, Chinese and Indians). The results showed that there was no significant difference in birth-weight estimation amongst the 3 clinicians as well as between the 3 ultrasound formulas used. There was however significant difference between these 2 groups when compared with the actual birthweight with clinical estimation being superior to ultrasound estimation in our population. This level of significance did not extend beyond 4,000 g fetal weight (actual) thus making both clinical and ultrasound estimation of fetal weight equally accurate after 4,000 g. This has important implications for developing countries where there is a lack of technologically advanced ultrasound machines capable of doing sophisticated functions like fetal weight estimations but has experienced clinicians who could perform this function equally well if not better.
A systematic collection of fetal morphometric measurements was started seven years ago in 1987 with the prospective entry of data into personal computer-based stations in the Department of Obstetrics and Gynaecology, Singapore General Hospital. A cross-sectional study was done, comparing 2392 Chinese fetuses with 2117 Malay fetuses and 459 Indian fetuses from 18 to 40 weeks. The mean values of the head circumference (HC), abdominal circumference (AC) and femur length (FL) of the 3 ethnic groups were analysed. There were no statistical significant differences in the head circumference and abdominal circumference of Chinese, Malay and Indian fetuses in Singapore. The Chinese and Malay fetal femur length appeared similar but were apparently shorter than the Indian femur length. Nomograms of head circumference, abdominal circumference and femur length were constructed for application to fetuses of all 3 ethnic groups.