Diagnostic accuracy of quantitative fetal fibronectin to predict spontaneous preterm birth: A meta-analysis

The potential role of the gingival crevicular fluid biomarkers in the prediction of pregnancy complications

Early and minimally invasive methods are required to predict the risk of multiple adverse pregnancy outcomes. A potential technique with growing interest utilizes the gingival crevicular fluid (GCF), a physiological serum exudate found in the healthy gingival sulcus and in the periodontal pocket in inflammatory conditions. Analysis of biomarkers in the GCF is a minimally invasive method that can be feasible and cost-effective. The potential use of GCF biomarkers along with other clinical indicators in early pregnancy may provide reliable predictors of several adverse pregnancy outcomes, therefore, reducing both maternal and fetal morbidities. Various studies have reported that increased or decreased concentrations of different biomarkers in GCF are associated with a high risk of developing pregnancy complications. In particular, such associations have been commonly demonstrated with gestational diabetes, pre-eclampsia, and pre-term birth. However, limited evidence is available regarding other pregnancy complications such as preterm premature rupture of membranes, recurrent miscarriage, small for gestational age, and hyperemesis gravidarum. In this review, we discuss the reported association between individual GCF biomarkers and common pregnancy complications. Future research is required to provide more solid evidence of the predictive value of those biomarkers in estimating women's risk for each disorder.

A prospective, double-blinded cohort study using quantitative fetal fibronectin testing in symptomatic women for the prediction of spontaneous preterm delivery

BACKGROUND

Spontaneous preterm birth (PTB) affects 6.5% of deliveries in Hong Kong. Quantitative fetal fibronectin (fFN) is under-utilised as a test for PTB prediction in Hong Kong. Our objective was to evaluate the effectiveness of quantitative fFN in predicting spontaneous PTB in women with symptoms of threatened preterm labour (TPTL) in our population.

METHODS

A prospective, double-blinded cohort study of women with a singleton gestation and TPTL symptoms presenting to a tertiary hospital in Hong Kong between 24 + 0 to 33 + 6 weeks was performed from 1st October 2020 and 31st October 2021. Women with vaginal bleeding, ruptured membranes, and cervical dilation > 3 cm were excluded. The primary outcome was to test the characteristics of quantitative fFN in predicting spontaneous PTB < 37 weeks. Secondary outcome was to investigate the relationship between fFN value and time to PTB. Test characteristics of quantitative fFN at different thresholds were evaluated.

RESULTS

48 women with TPTL were recruited. All had fFN testing at admission with the results being concealed from the obstetrician managing the patient. 10 mothers had PTB (< 37 weeks' gestation). 7/48 (15%) had a subsequent PTB within 14 days from testing and 5 (10%) delivered within 48 h. The negative predictive value (NPV) of predicting delivery within 14 days was 97.3% and 100% when using a cut-off of < 50ng/ml and < 10ng/ml respectively. Using > 200 ng/ml as cut-off can also reliably predict delivery within 48 h - 7 days with positive predictive value PPV of 100%; as well as PTB before 37 weeks.

CONCLUSIONS

Quantitative fFN has predictive value for spontaneous PTB prediction in symptomatic women in a Hong Kong population. fFN concentration could help clinicians rule out PTB and avoid unnecessary interventions and hospitalisation.

The use of fetal fibronectin and cervical length measurements in the prediction of spontaneous preterm birth in women with an Arabin pessary in situ

OBJECTIVES

The ability to predict spontaneous PTB (sPTB) has improved greatly, allowing women at risk to be managed with prophylactic interventions such as cervical cerclage and the Arabin pessary. Cervicovaginal fetal fibronectin (qfFN) concentration and ultrasound measurement of cervical length (CL) are the two most established tools to predict sPTB. There is however limited data regarding the predictive value of qfFN and CL tests following insertion of an Arabin pessary. Our aim was therefore to determine the clinical use of qfFN and CL measurements to predict sPTB in women fitted with an Arabin pessary.

STUDY DESIGN

This study is a secondary analysis on the SUPPORT trial data. Data were prospectively collected from women attending high-risk preterm surveillance clinics in 3 London centres between July 2015 and April 2020. The matched control group was pregnant women attending the same high-risk preterm surveillance clinics who had not received an Arabin pessary. Receiver operating characteristic (ROC) curves for prediction of birth by 34 and by 37 weeks' gestation were generated for qfFN and CL measurements combined for both study groups. A formal comparison of area under the curve before 34 weeks' gestation (AUC < 34 weeks) was made between the two study groups.

RESULTS

At our primary endpoint of sPTB < 34 weeks' gestation, qfFN was a good predictor of sPTB in cases with an Arabin pessary in situ (AUC, 0.79, 95% CI: 0.62-0.90) and no worse than the control group who did not have an Arabin pessary, (AUC 0.74, 95% CI: 0.48-0.96). CL had good prediction for sPTB < 34 weeks' gestation in the control group (AUC 0.76, 95% CI: 0.63-0.88) but was lower and non-significant in the Arabin pessary case group (AUC 0.60, 95% CI: 0.43-0.76).

CONCLUSIONS

This study showed that cervicovaginal qfFN concentration is equally reliable in the prediction of sPTB in pregnant women at increased risk of sPTB with and without an Arabin pessary in situ, and significantly better than CL measurement alone for predicting delivery before 34 weeks. This commonly used test therefore has utility in predicting sPTB in pregnant women fitted with an Arabin pessary.

Current Resources for Evidence-Based Practice, September 2021

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes an assessment of safety of birth centers in the United States and commentaries on reviews focused on aspirin prophylaxis in pregnancy and the new gestational weight gain evidence summary from the United States Preventive Services Task Force.