Fetal fibronectin assay may reduce management cost of preterm labour: an interval analysis

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.

Implementation of foetal fibronectin testing: Admissions, maternal interventions and costs at 1 year

Foetal fibronectin testing (fFN) has a high negative predictive value for preterm delivery, but it has a cost implication. This two-stage prospective study evaluated the real patient costs and clinical impact of introducing the fFN test in women presenting acutely with threatened preterm labour in a tertiary UK obstetric hospital. Introduction of the fFN test for women with threatened preterm labour reduced antenatal admissions and in utero transfers, and reduced steroid treatment and tocolysis, even at 1 year after implementation. The total number of bed days for women with threatened preterm labour who did not deliver during admission fell from 132 (mean 8.8 days) to 25 days (mean 3.6 days). The mean cost of admission per woman before introduction of the fFN test was £1032 (95% CI £880 to £1184); after it was £339 (95% CI £261 to £417). In this small single centre study, the introduction of the test produced a cost saving of £693 per woman (95% CI, £464 to £922) which over 12 months potentially saves £74844 (95% CI £50,112 to £99,576). Further studies are needed to formally evaluate the cost-effectiveness of the fFN test and its impact on clinical decision-making in large populations.

Cost-effective standardization of preterm labor evaluation

OBJECTIVE

The purpose of this study was to determine the effect of a standardized evidence-based protocol for preterm labor evaluation on resource use and obstetrics outcomes.

STUDY DESIGN

We conducted a retrospective 12-month observational study of patients with symptoms of preterm labor at the Mayo Clinic. All patients underwent triage evaluation per a standardized protocol with a combination of cervical length measurement with contingent fetal fibronectin assay.

RESULTS

Of 201 patients who underwent evaluation, 3 women delivered within 7 days, and only 1 woman delivered after a negative evaluation. Mean gestational age at evaluation was 29 weeks 1 day, and delivery was at 38 weeks 3 days of gestation, with an average interval of 57.4 days until delivery. The rate of hospital admission was reduced by 56%, compared with the previous year; an estimated annual cost saving was $39,900.

CONCLUSION

Implementation of a standardized protocol for evaluation of preterm labor reduces the rate of unnecessary hospital admissions for observation with consequent significant reduction in expenses.