Evaluation of the dating of gestation via the growth adjusted sonographic age method

We compared the actual delivery dates of 248 normal pregnant women to the estimated dates of confinement (EDC) calculated from one biparietal diameter measurement (BPD) between 18 and 26 weeks of gestation and to the EDCs corrected by the growth adjusted sonographic age ( GASA ) method. The dating of gestation by those two ultrasound methods also was compared to the calculation of the gestational age from the last menstrual period in a subgroup of 61 women with highly reliable clinical data. The GASA method had no advantage over the dating of gestation using one single BPD measurement obtained before 26 weeks, nor over the dating of gestation using reliable menstrual data.