Fetal fibronectin and endovaginal ultrasound in the management of preterm labor—a review of the evidence

Abstract

Objective: Spontaneous preterm delivery (PTD) complicates 10% of pregnancies. Preterm labor (PTL) often precedes PTD. Fetal fibronectin assays (fFN) and endovaginal ultrasound (EVUSD) identify women likely to deliver preterm. We sought to review the literature on fFN and EVUSD in PTL risk assessment.Methods: We worked as part of the AHCPR Evidence Report on the Management of Preterm Labor. With ACOG and an advisory group, we developed search criteria. We did an exhaustive literature search, including the gray literature, for articles in English, French, or German from 1966 to 1998 for randomized trials and observational studies of fFN and EVUSD in women with PTL, without membrane rupture, both inpatient and outpatient. Two reviewers masked to authorship and journal established final inclusion eligibility. Only 16 studies evaluated fFN and EVUSD in symptomatic women. A methodologist and a clinician (also masked) abstracted data on birth outcomes and test performance characteristics; a third review resolved discrepancies.Results: We focus on fFN and EVUSD for assessing risk of preterm birth. We will summarize sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. Estimates are on aggregate data from all 16 studies, evaluating fFN in 1,921 women and EVUSD in 476.Conclusions: We will present the findings and recommendations of the project team.