[FETAL WEIGHT CHARTS IN THE ISRAELI POPULATION].

Background: Sonographic estimated fetal weight is performed by measuring the fetal organs' biometry and introducing the data into a formula. The calculated value is then compared with reference charts and serves as a critical component in pregnancy follow-up. Ideally the charts should be appropriate to the specific population.

Objectives: To display and validate sonographic based Israeli-matched, intrauterine fetal weight curves.

Methods: The international Hadlock and Souka formulas, were chosen and assessed using over 70,000 ultrasound examinations from Israel. Since the Souka formula is appropriate only after 30 weeks of pregnancy, we used Hadlock's formula for pregnancies under 30 weeks and the comparison between the Hadlock and Souka formulas was made thereafter. In order to evaluate the Israeli population charts, 6389 pregnant women were examined sonographically in the last three days of pregnancy, and the estimated fetal weights were compared with the actual newborn weights.

Results: Fetal weight charts were constructed. Both equations were efficient, but the combination of Hadlock formula until 30 weeks and Souka between 31 to 42 weeks tended to be more accurate.

Conclusions: We described fetal weight charts based on common equations, using biometric measurements derived from the Israeli population. We recommend the charts presented here as the universal reference for all the professionals involved in perinatal care in Israel.

Discussion: Fetal growth abnormalities are determined by the curve chosen. Birthweight curves may underdiagnose restrictions in fetal growth because of the disorders associated with preterm delivery. Sonographic biometric curves represent physiological growth more reliably.