Fetal fibronectin improves the accuracy of diagnosis of preterm labor

• Published in: American journal of obstetrics and gynecology Vol. 173; no. 1; pp. 141 - 145
• Main Authors: Iams, Jay D., Casal, David, McGregor, James A., Goodwin, T.Murphy, Seshadri Kreaden, Usha, Lowensohn, Richard, Lockitch, Gillian
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Philadelphia, PA Mosby, Inc 01-07-1995; Elsevier
• Subjects: Adult; Biological and medical sciences; Cervix Uteri - physiopathology; Female; Fetal Proteins - analysis; fibronectin; Fibronectins - analysis; Genital system. Mammary gland; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Obstetric Labor, Premature - diagnosis; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Pregnancy; prematurity; Preterm labor diagnosis; Sensitivity and Specificity; Time Factors; Uterine Contraction; Vaginal Smears; fibronectin; Preterm labor diagnosis; prematurity; Human; Premature delivery; Uterine cervix; Enzyme immunoassay; Muscle contraction; Fibronectin; Uterus; Dilatation; Smear; Delivery disorders; Female; Fetus; Diagnosis
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/0002-9378(95)90182-5

OBJECTIVE: Our purpose was to assess the utility of cervicovaginal expression of fetal fibronectin in the diagnosis of preterm labor.
STUDY DESIGN: Women seen between 24 and 34 weeks' gestation with symptoms of preterm labor, intact membranes, and cervical dilatation <3 cm were enrolled at five university medical centers. Cervicovaginal swabs were obtained and assayed for the presence of fetal fibronectin by means of a monoclonal antibody assay. Results were compared with cervical dilatation and uterine contraction frequency as indicators of interval to delivery and delivery before 37 weeks.
RESULTS: A total of 192 eligible women at a mean gestational age of 30.8 ± 2.9 weeks were enrolled from a population of 418 subjects screened. The rate of preterm birth was 32.3% (
62
192
). The mean interval from presentation to delivery was 25.3 ± 24.1 days in the 45 subjects with a positive fibronectin assay and 52.4 ± 24.8 days in the 147 subjects with a negative assay (
p = 0.0001). The sensitivity, specificity, and positive and negative predictive values of fetal fibronectin expression for delivery <37 weeks were 44% (
27
62
), 86% (
112
130
), 60% (
27
45
), and 76% (
112
147
). The fetal fibronectin assay was especially useful in predicting risk of delivery within 7 days (sensitivity 93% [
13
14
], specificity 82% [
146
178
], positive predictive value 29% [
13
45
], and negative predictive value 99% [
146
147
]) and was notably superior to both cervical dilatation >1 cm and contraction frequency greater than or equal to eight per hour (sensitivities 29% and 42%, specificities 82% and 67%, positive predictive values 11% and 9%, and negative predictive values 94% and 94%, respectively).
CONCLUSION: Cervicovaginal fetal fibronectin predicts delivery within 7 days more accurately than do cervical dilatation and contraction frequency in a population of women evaluated for early preterm labor.