Predicting preterm labour by cervical length measurement

Preeti Priyadarshani, Gurcharan Kaur


Background: This study was undertaken to ascertain the role of cervical length measurement by Transvaginal Ultrasonography as a predictor for preterm labour.

Methods: Routine Antenatal cases presenting to the O.P.D. of Obstetrics and Gynaecology at 18-24 weeks of gestation were enrolled and subjected to transvaginal ultrasound for measurement of cervical length. The STUDY group consisted of 50 patients with cervical length being </=25mm. The CONRTOL group consisted of 50 patients with cervical length being >25mm. Patients were followed up to observe the outcome of their pregnancies. The data was analyzed using SPSS version 15.0 software.

Results: The positive predictive value of cervical length </=25mm was 6%, 16%, 30% and 50% for delivery before 28, 32, 34 and 37 weeks respectively; the negative predictive value for the same was 100%, 100%, 98% and 86%. A cervical length of < 25 mm at the initial sonographic examination was associated with a relative risk (RR) of 15 for spontaneous preterm birth before 34 weeks and 3.75 for spontaneous preterm birth before 37 weeks. Maternal outcome was comparable in the study and control groups. However, the babies born in the study group had greater morbidities associated with prematurity, lower birth weight, higher NICU admission rates, longer duration of NICU stay and greater mortality rates as compared to the babies born in the control group.

Conclusions: Measurement of cervical length aids in early detection of patients who are likely to go into preterm labour and identification of high-risk group.



Transvaginal sonography, Cervical length, Preterm labour

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