Comparative study of ultrasonographic accuracy at 8-16 weeks of gestational age with the Naegele’s Revised Rule for delivery history

Determining the correct date of pregnancy and fetal age has a very important role in the management of pregnancy from the first trimester to delivery, which makes it  necessary to know the exact method in this field. Therefore, this study aimed to compare the accuracy of ultrasound at 8-16 weeks with Naegele’s Revised Rule of the delivery date. This study was performed on 50 pregnant women. After recording demographic information and age of delivery, sonography of weeks 8-16 and Naegel’s Revised Rule were also recorded. A Paired t-test was used to compare data. The results of our study showed that the average difference between the Naegele’s Revised Rule and real age was 3.52 days, which is a significant difference. However, the average difference between the estimated date by ultrasound and real age is 0.58 days, which is not a significant difference. Ultrasound is more accurate than the Naegele’s Revised Rule, which still did not differ significantly from the actual date of delivery by grouping by age, sex of the fetus, number of pregnancies, and deliveries. Ultrasound has more accuracy in accurately estimating the date of delivery, and therefore using this method and relying on it has more reliability than the Naegele’s Revised  Rule.