ABSTRACT
BACKGROUND: Perinatal morbidity and mortality increase in proportion to the time from waited date of labor to birth. A test helping to predict pregnancies is required, which also helps to predict pregnancies that will progress more than 41 weeks. OBJECTIVE: To determine the usefulness of fetal fibronectin in vaginal secretions to predict pregnancies that will progress 41 weeks or more. MATERIAL AND METHODS: A cohort and descriptive study was done in which 144 women with a pregnancy of 40 weeks or more were included. Fetal fibronectin was detected in cervix-vaginal secretions and time from the sample obtaining to birth was estimated. RESULTS: Seventy patients with positive fibronectin were recorded; 92% had labor in the following seven days from the sample obtaining (interval mean: 3.1 days). The remaining patients (n = 44) resulted with negative fibronectin; only 37.5% had spontaneous labor, but none of them during the first four days from the sample obtaining (mean: 7.9 days). CONCLUSION: Absence of fetal fibronectin in vaginal secretions is a good prognostic marker to identify patients who will achieve a pregnancy of 41 weeks or more (sensitivity of 70% and specificity of 84%; positive and negative predictive value of 75% and 80.7%, respectively, and relative risk of 10, CI 95%, 5.7-14.3). This method is useful to prevent perinatal complications inherent to the pregnancy of 41 weeks or more.
