Accuracy of Ultrasound to Determine Gestational Age in Third Trimester

Rapid and accurate determination of gestational age (GA) may be vital to the appropriate care of the critically ill pregnant patient and improve obstetric care through allowing the optimal timing of necessary interventions and the avoidance of unnecessary ones. Ultrasound scans are considered to be the most cost-effective, accurate and safe methods for measurement of various fetal parts in pregnant women. The aim of this research is to explore the accuracy of ultrasound in determining gestational age of fetus in third trimesters. Data collected for all pregnant women referred to the Maternity & Children’s Hospital in Jeddah. Only women with single live fetus were included in this study. Women who participated in the study were selected on following criteria: Regular menstrual cycles, known date of last menstrual period and previous live normal neonates in multipara. All scans were performed by a single ultrasonologist on one ultrasound machine. From collected data, it was found that out of 53 (100%) patients, 44 (84.62%) pregnant woman have different gestational age from US and last menstrual period (LMP). From this study we can conclude that the main method to follow fetus growth in third trimester not biparietal diameter (BPD) measurement only. The BPD in third trimester is not reliable and be useless when the patient pass 30 weeks and the BPD has to be side with other measurements when we take it in later trimesters to emphasize the normal growth of fetus and avoid wrong measurement of ultrasound.