Fetal Biometry in the Israeli Population: New Reference Charts.

BACKGROUND Selection of appropriate reference charts for fetal biometry is mandatory to ensure an accurate diagnosis. Most hospitals and clinics in Israel use growth curves from the United States. Charts developed in different populations do not perform well in the Israeli population. OBJECTIVES To construct new reference charts for fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL), using a large sample of fetuses examined at 14-42 weeks gestational age in a medical center and a community ultrasound unit located in two different regions of Israel. METHODS Data from the medical center and the community clinic were pooled. The mean and standard error of each measure for each week was calculated. Based on these, reference charts were calculated using quantiles of the normal distribution. The performance of the reference charts was assessed by comparing the new values to empiric quantiles. RESULTS Biometric measurements were obtained for 79,328 fetuses. Growth charts were established based on these measurements. The overall performance of the curves was very good, with only a few exceptions among the higher quantiles in the third trimester in the medical center subsample. CONCLUSIONS We present new local reference charts for fetal biometry, derived from a large and minimally selected Israeli population. We suggest using these new charts in routine daily obstetric practice.