PREDICTION OF GESTATION AGE BY USING TRANSVERSE CEREBELLAR DIAMETER IN THE SECOND AND THIRD TRIMESTERS USING ULTRASOUND

Abstract

Estimation of the correct gestational age for fetuses is quite important in distinguishing between the preterm and term infants in order to do the necessary medical intervention after birth mainly for the preterm infants, in which many parameters have been used to estimate the gestational age including biparital diameter, femur length, head circumference, and abdominal circumference. The aim of the study was to predict fetal gestational age in the second and third trimesters of pregnancy for a singleton gestation by using the fetal transverse cerebellar diameter, in which its diameter in millimeters was assumed to equal the fetal gestational age in weeks, and compare the transverse cerebellar diameter with biparital diameter and the femur length measurements used to estimate the gestational age for each fetus. A total of 50 gravid women at 15-38 weeks of gestation who attended for serial follow up ultrasound scan at the ultrasound department in (Al-enqas Al-shahida Nada medical center) were recruited in the study. Each pregnant woman had been scanned once. the biparietal diameter, Femur length, and transverse cerebellar diameter where obtained for each fetus and the data were analyzed by excel and SPSS in reference to the expected gestational age calculated from the last menstrual period for each woman. The expected gestational ages of the singleton fetuses were between 15-38 weeks (mean 26.74), in which 10 cases were between 15-20 week GA, 21 cases between 21-30 week GA, and 19 case between 31-38 weeks GA, which correspond to 20%, 42%, and 38% respectively. The study showed strong correlation between the transverse cerebellar diameter in millimeters and the expected gestational age in weeks in which the correlation R= 0.921. The paired t-test for significance showed a significant difference between the transverse cerebellar diameter in millimeters and the corresponding expected gestational age in weeks at P = 0.05, but however it showed no difference between 15-22 weeks of gestation which was statically III significant (P < 0.02) and R= 0.95 thus it can be used as a predictor for estimating the gestational age during this period. The study also showed a strong correlation between the estimated gestational age by the biparietal diameter and the expected gestational age, and between the femur length and the expected gestational age in which the correlation was R=0.973 and R=0.975 respectively, paired t-test for significance showed insignificant difference between the estimated gestational age by biparietal diameter and Femur length and the corresponding expected gestational at P = 0.05, thus, biparietal diameter and femur length can be used with confidence in estimating gestational age during 15-38 weeks of pregnancy.