Correlation of gestational age by sonographic measurement of fetal parameters in women in eastern Nepal with existing standard normograms.

ABSTRACT

This is the prospective study carried out to correlate gestational age by sonographic measurements of fetal parameters by normograms of Frank P Hadlock with the gestational age by Last Menstrual Period (LMP) (considered our standard) in various trimesters of normal pregnant women of eastern Nepal. Seventy normal pregnant women with regular menstrual cycles of eastern Nepal were evaluated in this study. Gestational age was calculated by Rempen (in case of Mean Sac Diameter) and Hadlock (in case of Biparietal Diameter, Head circumference, Femoral Length and Abdominal circumference) normograms. Calculations of gestational age was also done by LMP at the same time. Correlation of gestational age by Rempen and Hadlock with average of different fetal parameters in different trimesters was done with gestational age by LMP applying paired t test. On applying paired t test between gestational age by Mean Sac Diameter and Crown-Rump Length in the first trimesters, mean difference was only -3.58 days (significance < 0.01). It showed statistically significant difference though difference is little. Paired t test application in second trimester showed significant difference (-5.06 days) with gestational age by LMP at < 001 significance level. In 3rd trimesters, paired t test showed significant difference with gestational age by LMP with mean of difference -7.86 days. Significant difference between average gestational age by Hadlock and gestational age by LMP in 2nd and 3rd trimesters of pregnancy indicates that we should stantardise our measurements of different fetal parameters for estimation of gestational age.