Royal College of Obstetricians and Gynaecologists

A quantitative fetal fibronectin test may help improve diagnosis of preterm labour, according to results from the QUIDS study, which were presented at the Royal College of Obstetrics and Gynaecologists (RCOG) World Congress 2019 by Dr Sarah Stock, Senior Clinical Lecturer in Maternal and Fetal Health, University of Edinburgh, Scotland. Dr Stock was the Congress Medal Winner at RCOG 2019.

The clinical diagnosis of preterm labour that leads to delivery is notoriously challenging.

"Around a third of antenatal admissions and a third of in utero transfers are for women with symptoms and signs of preterm labour; however, fewer than one in ten of these women will actually deliver within the next 7 days," said Dr Stock.

"Treatment of these women is understandable. But unnecessary treatment has impact on already stretched maternity services and may have long-term consequences for mothers and babies," she added. "The consequences of being separated from family can be traumatic and can incur personal and financial cost."

A number of biochemical tests for impending preterm birth are available but, currently, UK clinical guidance recommends only a qualitative fetal fibronectin test with a single threshold of 50 ng/mL.

The quantitative fetal fibronectin test (which provides an absolute concentration of fibronectin in the cervical secretions) was used in this study. "Very recent NICE guidance suggests there is not enough evidence to use this test," Dr Stock said.

The aim of the QUIDS study was to develop a decision support tool for the management of women with symptoms and signs of preterm labour, based on a validated prognostic model using quantitative fetal fibronectin concentration, in combination with clinical risk factors.

The primary endpoint was to develop a validated prognostic model that would predict spontaneous preterm birth within 7 days of testing in women with signs and symptoms of preterm labour.

In the first part of the study, the researchers developed and validated their prognostic model. They created the model using data from a meta-analysis of five studies (including 1,783 women and 139 events of preterm delivery within 7 days of testing).

Risk factors identified in the first stage of the study for the prediction of preterm birth in the prognostic model included age, ethnicity, smoking, nulliparity and multiple pregnancy in addition to qualitative fibronectin.

In the second part of their study, the team tested their validated prognostic model in the real world in a prospective cohort study, which included 2,924 women.

The team then performed a net benefit analysis to see how the test would perform in clinical practice.

"We are happy with the validation of the model. It has good performance statistically and we hope it will have clinical utility and be useful for clinicians," said Dr Stock.

The team is now developing a user-friendly interface to support decision making. They also performed a health-economic analysis which showed that the tool would be cost effective if used in clinical practice. This analysis was not presented.