Diagnostic validity of cervicovaginal human chorionic gonadotrophin at 26–36 weeks of gestation as a biochemical predictor of preterm birth

Abstract

The aim of this study was to assess the diagnostic accuracy of qualitative and quantitative assay of human chorionic gonadotrophin (hCG) in cervicovaginal secretion as a biochemical predictor of preterm birth. A prospective study was conducted at Ain-Shams University Maternity Hospital, Cairo, Egypt. A total of 390 pregnant women were included in the statistical analysis: 90 women who presented with threatened preterm labor and 300 asymptomatic pregnant women with matched age, gestational age, bodyweight, parity and obstetric history. Qualitative and quantitative measurements of cervicovaginal fluid hCG at 26-36 weeks of gestation were performed to assess the risk for preterm birth. In women with threatened preterm labor (group 1) and asymptomatic pregnant women (group 2), preterm birth occurred in 35.6% and 9.3%, respectively. We analyzed predictive performances of qualitative and quantitative assay of hCG in cervicovaginal secretion, while combining group 1 and group 2. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of qualitative test, by the cut-off level of 25 mIU/mL, to predict preterm birth were 68.3%, 96.1%, 76.9%, 94.3% and 91.8%, respectively; those of quantitative test, by the cut-off level of 34.5 mIU/mL, were 100%, 98.5%, 92.3%, 100% and 98.7%, respectively. Both the qualitative and quantitative assessment of cervicovaginal fluid hCG at 26-36 weeks of gestation were valuable in the prediction of occurrence of preterm birth in the women who presented with threatened preterm labor as well as in the asymptomatic pregnant population.