Ultrasound assessment of the cervix in recognizing preterm delivery

Background:  Cervix is very important structure that separates the fetus from external environment, which we can visualize very precisely transvaginal ultrasonography. Sonographic examination allows visualization of the internal cervical os and the portion of the cervix that lies above the vaginal fornices, providing information that is inaccessible to digital examination. Cervical length in the pregnancy is one of the predictors of preterm delivery and diagnosis of cervical incompetence. Materials and methods:  We have investigated 57 pregnant women: 20 diabetic pregnant women, 8 with hypertension, 14 with cervical incompetence, and 15 in uncomplicated pregnancy. Transvaginal sonography was used to measure cervical length between 20 and 30 weeks gestation. Ultrasound examination was performed using 2000 with 5.0 MHz transvaginal transducer. Maternal age ranged from 19 to 39 years (mean 27.2 ± 8.3). The following measurements were obtained: endo-cervical canal length between the internal and external os, funneling of the cervix, funnel width, funnel length. Results:  The mean endo-cervical length measured in ultrasonography was 17.3 ± 5.2 mm in pregnancies delivered preterm (n = 7) and 33.4 ± 9.6 mm in pregnancies delivered at term (nP). The 11 pregnant women with cervical incompetence were treated with cervical cerclage, eight of them delivered at term and three preterm. The mean endo-cervical length was 10.4 mm ± 3.0 and in all cases we observed funneling of the cervix in this group. Endo-cervical length was 25 mm in 75% pregnant women, who delivered after 37 weeks of pregnancy. No significant relationships were shown between length of the cervix in pregnancy complicated by diabetes mellitus, hypertension and uncomplicated pregnancy. The mean endocervical length in diabetic pregnancy was 34.7 ± 4.7 mm; pregnancy with hypertension 32.9 ± 5.8 mm and uncomplicated pregnancy 35.6 ± 3.8 mm. Conclusion:  Cervical length measured by ultrasonography between 20 and 30 week of pregnancy is very important predictor of preterm delivery. No significant relationships were shown between the length of the cervix and investigated pregnancy complications.