A validation study of ultrasonic foetal weight estimation models for Hong Kong Chinese singleton pregnancies

MW Pang, TN Leung, TK Lau
Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong

OBJECTIVE. To validate the published regression models for ultrasonic foetal weight estimation in Hong Kong Chinese singleton pregnancies.

DESIGN. Prospective cohort study.

SETTING. Regional hospital, Hong Kong.

PARTICIPANTS. One hundred and fourteen Hong Kong Chinese women with singleton pregnancy at term (37-42 weeks).

MAIN OUTCOME MEASURES. The birth weight of the neonate was used to validate the ultrasonic foetal weight estimation models. The ultrasound used to collect the data was performed within 2 days prior to delivery.

RESULTS. Foetal weight estimation models published by Hadlock and Woo have a high intraclass correlation coefficient of 0.86. Woo's regression model has the least mean difference (0.2 g; 95% limits of agreement, -569.4 to 569.8 g) and Hadlock 3 has the smallest limits of agreement (-114.6 g; 95% limits of agreement, -663.4 to 434.2 g) among the models tested.

CONCLUSIONS. Woo's regression model of foetal weight estimation gave the least mean difference and the actual birth weight for our local population were within the acceptable limits of agreement.

Hong Kong Med J 2004;10:384-8

Key words: Birth weight; Fetal weight; Infant, newborn; Pregnancy; Ultrasonography