EP08.50: Comparative assessment of antenatal growth charts in estimating femur length in Indian population

To assess the difference in femur length (FL) centiles using three antenatal growth charts (GC) i.e. FMF, MEDISCAN and HADLOCK GCs. The study included 573 ultrasounds in 396 patients. The FL centiles used in the dataset were obtained from the converter provided on FMF website, Mediscan from Sonocare software and Hadlock v for their respective GCs. Inclusion criteria were low risk, singleton pregnancies, gestational age between 18 to 40 weeks, availability of a dating scan between 8 to 14 weeks. All the women were of Indian origin. Exclusion criteria were major structural anomalies. The FL at two gestational age (GA) groups 18-28 weeks and 28 to 40 weeks was compared between the three GCs i.e. FMF, MEDISCAN, HADLOCK. At GA of 18-28weeks, 1% of fetuses had FL < 5 centile, 1% were between 5 to 10 centile, 84.2% between 10-90 centile and 13.8% were >90 centile according to FMF GC. According to MEDISCAN GC 1% fetuses had FL <5 centile, 11% between 5 to 10 centile, 92.3% between 10-90 centile and 0.5% were >90 centile. According to HADLOCK GC 0% fetuses had FL at <5 centile, 3.1% were between 5 to 10 centile, 96.9% were between 10-90 centile and 0% were >90 centile. At GA of 28-40 weeks, 4.2% of fetuses had FL < 5 centile, 3.2% between 5 to 10 centile, 82.2% between 10-90 centile and 10.3% were >90 centile according to FMF GC. According to MEDISCAN GC 2.9% fetuses had FL <5 centile,3.4% between 5 to 10 centile, 82.2% between 10-90 centile and 11.4% were >90 centile. According to HADLOCK GC 1.1% fetuses had FL at <5 centile, 15.4% were between 5 to 10 centile, 82.8% were between 10-90 centile and 0.8% were >90 centile. The study confirms the difference in the three GCs for FL centiles across the two gestational age groups.