Comparison of cervical-length measurement with cervicometer and transvaginal ultrasound in mid-pregnancy

Abstract

Direct measurement of the cervical length using a cervicometer has recently been used, which is cheaper and easier compared to transvaginal ultrasound; so, makes it more accessible. It seems that measuring the length of the cervix by a cervicometer is an acceptable indicator compared to transvaginal ultrasound to measure the length of the cervix and of course, the results obtained from the measurement during different ages of pregnancy as well as the risk status of pregnant women in terms of premature birth be different For this reason, the current study aims to compare cervical length measurement with cervicometer and vaginal ultrasound in mid-pregnancy. Materials and Methods: In this cross-sectional study, pregnant women with a gestational age of 14 to 24 weeks who were referred to the perinatal clinic were included in the study. Pregnant women were divided into two groups, Low Risk and High Risk, in terms of the risk of spontaneous premature birth. Also, based on the defined cut point for BMI at the beginning of the study, which was equal to 25 kg/m2, patients were divided into two groups, Normal and High. In the evaluation, the length of the cervix was measured and recorded by cervicometer and transvaginal ultrasound at same time. Patient information including age, gestational age, previous obstetric history, underlying diseases, height, weight, BMI, smoking, previous history of SPTB, history of cervical surgery, age at birth, premature birth with clinical indication, fetal death after one week 20 pregnancies, miscarriages under 20 weeks, term births (over 37 full weeks) were registered. Results: The frequency of preterm birth in patients with high BMI was significantly higher than in patients with normal BMI (46.6% vs. 24%; p=0.045). A comparison of cervical length measured in patients with normal BMI showed that the value measured by ultrasound method is significantly higher than by cervicometer method (35.1 mm vs. 29.6 mm; p=0.001). Also, the same result was obtained in patients with high BMI (31.6 mm vs. 27.1 mm; p=0.001). The average difference between the two measurement methods was higher in patients with normal BMI than in patients with high BMI, but no statistically significant difference was observed. The cut-off point for the length of the cervix in the cervicometer method is 24.5 mm (sensitivity 89.5% and specificity 66.7%) in patients with normal BMI; and in patients with high BMI, the cut-off point for cervical length in cervicometer is 24.5 mm (sensitivity 93.5% and The specificity was 70.4%).