Estimation of nomograms according to Crown-Rump Length in Mongolian population / Монголын Анагаах Ухаан

ABSTRACT

GoalThis study was performed to construct Mongolian ethnic specific crown-rump length (CRL)nomogram and to compare its ability to predict gestational age with previously published widelyused nomograms in the world.Materials and MethodsA regression model was developed for estimation of gestational age using CRL measurements of1170 singleton fetuses in the Mongolian population. Measurements were obtained by placing thecalipers of the ultrasound machine from the crown to the rump. The appropriateness of previouslyestablished widespread CRL nomograms for predicting the gestational age was assessed in theMongolian population to determine comparability between nomograms.ResultsCRL corresponds to other nomograms up to 9 weeks of gestational age. There is a 4-5mm differenceof Robinson Hadlock; 7mm of Osaka at 10-12 weeks but the same with Campbell, 4 mm long ofCampbell at 13 weeks.Conclusions:CRL measurements are used as a reliable method for estimation of the gestational age as well asa baseline for comparing gestational ages later. CRL corresponds to other widely used nomogramup to 9 weeks gestational age. There is a 3mm differences of M.A.Esetov, 4-5mm Robinson, andHadlock; 7mm of Osaka at 10-12 weeks but the same with Campbell, 4 mm long of Campbell at13 weeks. Difference with the established nomograms may be due to ethnic differences of theMongolian fetal development. After 13 weeks, CRL measurement is unreliable due to flexion of thefetus.