ABSTRACT
Cervical inability to preserve pregnancy is called cervical insufficiency. On-time diagnosis of cervical insufficiency is important for taking appropriate preventive actions. Endovaginal sonography is a powerful predictor for spontaneous preterm pregnancy loss. Importance of cervical length measurement is to diagnose cervical insufficiency and to decide on cerclage. In this study, we evaluated endovaginal sonography assessment of cervical length changes during a normal pregnancy. In a prospective cross-sectional study endovaginal sonography on 150 pregnant women [50 in every trimester] was performed to measure cervical length and mean of the cervical lengths in the three trimesters was compared together by one way ANOVA test. The patients were followed until labor. Twin pregnancies and cases with history of uterus curettage, cervical anomalies, preterm labor and cerclage were excluded from the study. Mean of the cervical length in the first, second and third trimesters of pregnancy respectively were 39, 40.7 and 39.3 mm respectively. In addition, the minimum and maximum length of cervix in the same trimesters were 28 and 56 mm, 26 and 52 mm, 27 and 52 mm respectively. Minimum cervical length was seen in the first pregnancy and maximum cervical length was seen in past NVD. No significant statistical differences were seen between the means of cervical length in the three trimesters of pregnancy or maternal age. However, there was a significant statistical difference between mean cervical length and maternal parity [p=0.05]. The mean cervical length in three trimesters was 39 mm and considered as an accepted value for mean cervical length in different trimesters. According to presence significant correlation between cervical mean lengths and multiparity with no preterm labor history, it may be safer if there is no preterm labor history in a multiparity pregnant woman