Evaluation of Gestational Age Based on Ultrasound Fetal Growth Measurements

ABSTRACT

Monitoring fetal growth and assessing its predictors have important place in antenatal care management. Accurate prediction of gestational age (GA) and birth weight (BW) is clinically important. Standard growth curve chosen should be evaluated to see if it satisfies the criteria for a valid assesment. In this paper, for the purpose of contributing to develop national standards and to evaluate Hadlock's standard data pertaining to 1411 fetuses were examined. Of 1411 normally growing fetuses, one measurement for AC, BPD and FL was taken by ultrasound. GA was assessed via menstrual history which is also confirmed by ultrasonography. Several variables, AC, BPD, FL, FL/AC, BPD/FL and dependent variables (GA & BW) were modelled mathematically. Percentile values, correlation coefficients were calculated and well functioning regression equations were produced for the fetal growth evaluation. Simple correlation model re-confirmed that AC, BPD and FL were well predictors of GA. Via modelling by multivariate regression analysis (adj. R2=937), GA=4.945 (95% CI 4.661- 5.654) + .606 AC + .105 BPD + .286 FL can be estimated. It couldn't be possible establishing an appropriate equation for prediction of BW vith current data. Our study is intended to draw an attention on requirement of national standards although Hadlock's standard growth curve may evaluate fetal development accurately. Forming comprehensive cohort group is under our consideration. The equation we developped (shown in the results), might be a working contribution.