Comparison of Cervical Parameters by Three-Dimensional Ultrasound according to Parity and Previous Delivery Mode

Background: We would like to find out that whether the patient's parity, previous delivery mode and previous labor could influence cervical parameters. Cervical length, volume and width were measured using two-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound on normal pregnant women. Method: This study was conducted between January 2009 and December 2010 in singleton pregnant women who were admitted for routine antenatal care at hospitals in affiliation with the Catholic University, Seoul, Korea. The study group was classified by parity (nullipara and multipara) and previous delivery mode (cesarean section group and vaginal delivery group). The previous cesarean section group was divided by elective group who did not undergo labor and labor group who underwent labor. Cervical parameters such as cervical length, volume and width were measured using 2D and 3D ultrasound examinations in the first and second trimesters and the results were analyzed between those groups mentioned above. Results: One hundred and twenty-one pregnant women in their 1st trimester and 233 pregnant women in their 2nd trimester (a total of 354) were enrolled in this study. Cervical parameters were not statistically significant from parity, nor previous delivery mode and previous labor in 1st trimester. Cervical volumes were not statistically significant from nullipara and elective cesarean section groups (35.96±9.81 vs. 34.73±9.75 cm3), but the nullipara groups were significantly lowered in the vaginal group (35.96±9.81 vs. 43.10±11.87 cm3) in 2nd trimester. For the nullipara group, cervical widths were not statistically significant in the elective cesarean section group but these were significantly lower than labor and previous vaginal group in the 2nd trimester. Conclusion: The cervical volume and width have an influence on parity, previous delivery mode and labor in the 2nd trimester.