Impact of the fetal fibronectin assay on admissions for preterm labor

The aim of the study was to determine whether use of the fetal fibronectin assay would decrease the number of admissions to labor and delivery for diagnosis and treatment of preterm labor.

A prospective cohort design was used to compare preterm labor admissions during a 12-month period of fetal fibronectin assay use (study) against a baseline period before fetal fibronectin assay was implemented as standard protocol. Patients coming to the physician's office or hospital with signs and symptoms of preterm labor had a sample obtained for fetal fibronectin assay per labeling criteria. Comparisons were made with the Mann-Whitney U test, independent Student t test, chi2 test, and Fisher exact test. P <.05 was considered significant.

There was no difference noted in the number of deliveries between the baseline and study years. During the study year 251 of 330 patients evaluated for preterm labor met study criteria and had the fetal fibronectin assay completed. Eight patients did not have fetal fibronectin assay results available because of specimen handling errors, leaving 243 subjects available for study. Compared with the baseline year, the study year had significantly fewer admissions for preterm labor, preterm labor admissions per patient, and prescriptions written for tocolytic agents. In addition, the length of stay per admitted patient was significantly reduced. The study population had no differences in neonatal outcomes from the baseline population in terms of deliveries at <35.0 weeks' gestation, number of admissions to the neonatal intensive care unit, neonatal intensive care unit length of stay, or days of ventilatory support per patient admitted to the neonatal intensive care unit.

Use of the fetal fibronectin assay resulted in significantly reduced preterm labor admissions, length of stay, and prescriptions for tocolytic agents. No negative impact on neonatal outcomes was observed. Reductions in admissions for preterm labor and in charges per admission resulted in approximately $486,000 saved during the study period. A trend toward increased corticosteroid administration (for neonates ultimately admitted to the neonatal intensive care unit) was noted.