Ultrasound dating-curve analysis in the assessment of gestational age

The accurate assessment of gestational age is very important in everyday practice. By the use of multiple regression analysis, in a longitudinal study, ultrasound dating-curves were calculated for the crown-rump length, biparietal diameter, femur length, humerus length, binocular distance and transverse cerebellar diameter. All the examined parameters showed a good statistical correlation with gestational age; however, the earlier the estimation of the gestational age, the more accurate it is. The crown-rump length has been shown as the best parameter during the first trimester. Later on, the other biometric parameters become easier and more reliable. If determination of gestational age is required during the third trimester, the use of multiple parameters is recommended.