Qualitative human chorionicgonadotropin testing of cervicovaginal washings for the detection of preterm premature rupture of membranes

This study was performed to determine whether a qualitative human chorionicgonadotropin (hCG) test using cervicovaginal washings obtained from pregnant women is a useful predictor of recent preterm premature rupture of the membranes (PPROM). Study design A prospective observational analysis of qualitative hCG testing on cervicovaginal washings in patients with either known PPROM or with intact membranes was performed. Patients with singleton gestations between 24 and 34 completed weeks were included. PPROM patients had documented comfirmatory tests, including visualized pooling of amniotic fluid in the vaginal vault that was nitrazine-positive and demonstrated ferning. Those with vaginal bleeding or an anomalous fetus were excluded. Before collection, all patients were screened for bacterial vaginosis and trichomoniasis. Washings were then collected from the posterior vaginal fornix with the use of a 5-mL sterile saline irrigation and aspiration technique. Samples were then agitated manually and applied to the Quickvue Onestep qualitative pregnancy test (Quidell, San Diego, Calif) with a threshold of 25 mIU/mL. Data were analyzed with the t test, χ2, and Fischer exact tests. Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were calculated. When applicable, all 2-tailed P< .05 were considered significant. Results Fifty-two patients were enrolled in the study with 24 in the PPROM group and 28 in the control group. The 2 groups were similar with respect to demographic characteristics and wet preparation results. The mean gestation age was 31.4 ± 2.4 (X ± SD) and 30.8 ± 2.7 weeks in the PPROM and control groups, respectively. The hCG test was positive in 19 (79%) of the PPROM patients and in 1 (3.6%) of the controls (sensitivity 79%, specificity 96%, PPV 95%, NPV 84%). Conclusion Qualitative hCG testing of cervicovaginal washings appears to be an useful predictor of PPROM.