Ultrasound evaluation of cervical length in the second trimester of pregnancy: The impact of cesarean section and ethnicity

Abstract

Background and Objective: The sonographic assessment of cervical length (CL) is an important part of ultrasound evaluation in the second trimester of pregnancy. There are specific maternal characteristics and obstetric history which affect the CL. This study aims to assess the influence of mode of delivery and ethnicity on the CL in women with divergent ethnicity. Materials and Methods: A prospective cross-sectional study was designed, including 109 pregnant Sudanese women in the second trimester. They were investigated with transvaginal ultrasonography (TVS) using high-frequency 7.5-MHz probe to assess the CL. The participants were categorized according to their ethnicity and regions. The results were analyzed using analysis of variance (ANOVA) and Student's independent t-test in the SPSS program version 16 (IBM Inc.) and P > 0.05 considered to be statistically significant. Results: The mean TVS CL was 38.2 mm in the second trimester of pregnancy. The CL of northern Sudanese women was significantly longer than women from western, southern and eastern Sudan (P = 0.041). The mean CL of previous cesarean-sectioned women was 37.7 mm which was statistically significantly shorter than those who delivered normally (P = 0.03). The CL was not significantly different in multiparous compared to nulliparous women (37.83 vs. 37.78 mm, P= 0.77). Maternal age and gestational age did not significantly change the CL in second and third trimesters, P= 0.69 and 0.99, respectively. Conclusions: In the light of this study, cesarean section and ethnicity were considered to be significant factors that affect the CL in the second trimester of pregnancy. We suggest transvaginal sonographic measurement of CL as a part of a routine ultrasound evaluation in the second trimester.