Fetal growth assessment at 11-14 wks of gestation based on a population anomaly screening program in central-eastern Poland

Objective: Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on sonographic biometry and, second, to derive reference curves for normal fetal growth assessed from 11 weeks 0 days to 13 weeks 6 days of gestational age. Methods: A prospective cross-sectional study included a cohort of consecutive 648 pregnancies who underwent routine first-trimester aneuploidy screening between 2009 and 2013. Sonographic measurements included crown-rump length (CRL), biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL). For each measurement regression models were fitted to estimate the mean and SD. The 3 rd , 5 th , 10 th , 25 th , 50 th 75 th , 90 th , 95 th , and 97 th percentiles were estimated at each day of studied gestational age (GA) by least squares regression for the mean and SD of the CRL, BPD, AC’s functions of GA. R(2) and associated P values for the relationships between the CRL, BPD, AC, FL and birth weight at delivery and perinatal complications were calculated. Results: Final group consisted of 321 singleton pregnancies with known perinatal outcomes. Data characterizing maternal and newborns outcomes are presented. We were able to measure CRL, BPD and NT in all 321 fetuses, whereas AC was measured in only 113 cases and FL in 317 cases. We have noted that even in women with regular cycles and certain dating of LMP, there was a discrepancy in the gestation calculated from the LMP and CRL of more than 7 days in almost 20% of the cases. These results indicate that pregnancy dating should be rather based on CRL than LMP. Scatterplots of individual measurements and fitted centiles indicated good agreement with the calculated medians. The plots indicating 3 rd , 10 th , 90 th and 97 th centiles for CRL, BPD, AC and FL against gestational age are presented. Both the CRL and FL correlated significantly and strongly with biparietal diameter and abdominal circumference. Conclusions: This pilot study provides new charts for ultrasound fetal growth assessment in a singleton pregnancy based on screened population of Polish women. Our results indicate the necessity to modify and adjust the standard growth charts for ultrasound parameters existing from the last 30 years with newer fetal biometric measurements.