Measurement of cervical biometry using transvaginal ultrasonography in predicting preterm labor

CONTEXT: Preterm delivery is associated with high perinatal mortality and morbidity. Although detection of fetal fibronectin in cervical can predict preterm labor, but it is not available in lower source setting area. So, cervical length measurement by ultrasound can be used as an alternative to fetal fibronectin for predicting preterm labor. AIMS: To find out the effectiveness of assessment of cervical length by endovaginal ultrasonography in predicting preterm delivery. SETTINGS AND DESIGN: The study was conducted in the infertility clinic of Mahatma Gandhi Medical College and Research Institute, Pondicherry from January 2010 to July 2011. MATERIALS AND METHODS: A total of 130 women with singleton gestation were studied with transvaginal ultrasonography (TVS) to assess the cervical changes (cervical length, dilation of internal os, presence of funneling) between 22 weeks and 24 weeks of gestation. The gestational age at delivery in women with cervical length with ≥25 mm were compared with those of <25 mm. STATISTICAL ANALYSIS USED: Statistical analysis was done using Chi-square test. The P value is <0.001 which is statistically significant. RESULTS: The mean cervical length in the study population was 33.16 mm. 16 women had cervical length <25 mm at mid trimesters can out of which 13 (40.62%) went for spontaneous preterm delivery. The relative risk of preterm delivery increased as the length of the cervix decreased. The P value is <0.001 which is statistically significant. A significant difference was found between multigravida at risk of preterm being 62.5% compared to primigravida which was 37.5%. CONCLUSIONS: The risk of spontaneous preterm delivery is increased in women who are found to have a short cervix by TVS during pregnancy and it is a sensitive, simple and cost effective method of assessing risk of preterm delivery.