THE PRESENCE OF FETAL FIBRONECTIN IN THE CERVICOVAGINAL SECRETIONS OFWOMEN AT TERM - ITS ROLE IN THE ASSESSMENT OF WOMEN BEFORE LABOR INDUCTION AND IN THE INVESTIGATION OF THE PHYSIOLOGICAL-MECHANISMS OF LABOR

OBJECTIVE: Our purpose was to determine whether the presence of fetal fibronectin in cervicovaginal secretions of patients undergoing induct ion of labor reflected the cervical state and ultimately the ease of i nduction of labor. STUDY DESIGN: A prospective observational study of 103 patients undergoing induction of labor at term was conducted at Li verpool Maternity Hospital, a large university teaching hospital. We s tudied the women after 37 completed weeks of pregnancy. A Dacron (Adez a Biomedical, Sunnyvale, Calif.) polyester swab specimen was first tak en from the endocervix for assessment of the presence of the fetal fib ronectin. The cervix was then assessed by digital vaginal examination and scored with a modified Bishop's score. The fetal fibronectin swab was processed at the bedside with a membrane immunoassay kit specific for fetal fibronectin. A score was ascribed depending on the strength of the fibronectin reaction determined by the intensity of the color c hange on the plate, the presence of fetal fibronectin resulting in a s core of 1 to 4. The patient was subsequently managed according to the standard induction protocol of the unit. The clinicians involved in th e patient's care were blind to the result of the fetal fibronectin swa b. RESULTS: There was a good correlation between the modified Bishop's score and the fetal fibronectin score (r = 0.58, p < 0.001). To predi ct a latent phase of <8 hours, a fetal fibronectin score of 3 or 4 has a sensitivity of 73% with a specificity of 83% and a modified Bishop score of greater than or equal to 4 has a sensitivity of 75% and a spe cificity of 73%. For delivery within 12 hours of induction of labor a fetal fibronectin score of greater than or equal to 3 has a sensitivit y of 61% and specificity of 83% compared with the modified Bishop scor e of greater than or equal to 4, which has a sensitivity of 76% and a specificity of 72.5%. CONCLUSIONS: The fetal fibronectin score is as g ood as the modified Bishop score as an index of the ease with which in duction of labor may be performed. This would imply that it also refle cts the proximity of the onset of labor. The presence of fetal fibrone ctinin cervicovaginal secretions is therefore a marker of the changes in the cervix and membranes that precede labor regardless of the gesta tional age.