Accuracy of qualitative maternal cervicovaginal fetal fibronectin test in predicting spontaneous preterm birth in symptomatic pregnant women

Background: The incidence of preterm birth is increasing worldwide. Preterm birth is a common cause of neonatal morbidity and mortality commonly associated with low-birth weight and deficiency of lung surfactants in the newborn. Children who were born preterm have higher rates of cerebral palsy, neurodevelopmental anomalies, learning disabilities, and respiratory illnesses compared with children born at term with attendant psychosocial and financial burden on the parents or carers. These problems may be minimized via the use of a preterm birth prediction test such as the maternal cervicovaginal fetal fibronectin test (FFT) to determine those women in genuine preterm labor and at a higher risk for preterm birth. Effective treatment can then be focused on this group of women to reduce the incidence of preterm birth. However, the FFT in preterm birth prediction is underutilized in Nigeria. Aim: To determine the role of cervicovaginal fetal fibronectin testing as a predictor of spontaneous preterm birth in symptomatic pregnant women in a local setting. Setting: This study was conducted at the obstetrics unit of the Department of Obstetrics and Gynaecology at the Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ile-Ife, Osun state, Nigeria. The OAUTHC comprises two obstetrics units – Ife Hospital Unit (IHU) and Wesley Guild Hospital Unit at Ilesha (WGH). Design: Cross-sectional, descriptive study. Methods: In this study, 182 booked and unbooked singleton antenatal mothers between 28 weeks and 36 weeks 6 days gestation who had symptoms suggestive of preterm labor were recruited. An interviewer administered questionnaire was filled for each subject and a sterile speculum vaginal examination was then performed to obtain a specimen of the subject's cervicovaginal secretion using a sterile cotton swab. A qualitative FFT was done on each sample collected, then recruited mothers were monitored till delivery and further data obtained. Outcome Measures: The main outcome measures were the sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of FFT in predicting spontaneous preterm birth in symptomatic pregnant women. Results: A total of 182 women presenting with symptoms suggestive of preterm labor were recruited: 171 (93.96%) women delivered at term, whereas 11 (6.04%) women had preterm birth with a calculated preterm birth rate of 7.33 per 1000 deliveries during the study period. Also, 7 (3.85%) women had a positive FFT, while 175 (96.15%) women had a negative test. FFT had a sensitivity, specificity, PPV, and NPV of 9.09%, 96.49%, 14.29%, and 94.29%, respectively; a LR+ and LR- of 2.59 (95% confidence interval, CI, 0.34–19.68) and 0.94 (95% CI, 0.78–1.14) respectively; a relative risk of 2.59 (95% CI, 0.341–19.675); a calculated accuracy of 91.21% (95% CI, 86.12%–94.89%); and an area under the receiver operating characteristic curve of 0.60. Conclusion: The high NPV of fetal fibronectin sampling in a population of pregnant women with symptoms supports less intervention for patients with negative results.