Predicting preterm birth: Cervical length and fetal fibronectin

Abstract

Spontaneous preterm birth remains the leading cause of neonatal morbidity and mortality worldwide, and accounts for a significant global health burden. Several obstetric strategies to screen for spontaneous preterm delivery, such as cervical length and fetal fibronectin measurement, have emerged. However, the effectiveness of these strategies relies on their ability to accurately predict those pregnancies at increased risk for spontaneous preterm birth (SPTB). Transvaginal cervical shortening is predictive of preterm birth and when coupled with appropriate preterm birth prevention strategies, has been associated with reductions in SPTB in asymptomatic women with a singleton gestation. The use of qualitative fetal fibronectin may be useful in conjunction with cervical length assessment in women with acute preterm labor symptoms, but data supporting its clinical utility remain limited. As both cervical length and qualitative fetal fibronectin have limited capacity to predict preterm birth, further studies are needed to investigate other potential screening modalities.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome – 2019 Update

“…There is often warning of impending preterm delivery, and in these cases a need to consider interventions to prolong gestation or reduce risk of an adverse outcome by “preparing” the fetus. Cervical length measurement possibly in combination with a biomarker may determine which women are actually at risk of delivery within 7 days and allow more judicious use of antenatal treatments [14]. Extremely preterm babies should, if possible, be transported in utero to tertiary centres where appropriate skills are available; best outcomes are achieved for babies born in centres with a high throughput of VLBW babies [15].…”

Amniotic fluid proteomic signatures of cervical insufficiency and their association with length of latency

“…4,7,[10][11][12][13] In either case, emergency cervical cerclage is contraindicated in the presence of intra-amniotic infection as it carries a significant risk of maternal sepsis and poor neonatal outcome. Elevated levels of cervicovaginal fetal fibronectin, an extracellular matrix protein, 22,23 and phosphorylated insulin-like growth factor binding protein-1 (phIGFBP-1), a protein involved in placental development, have both been associated with risk of preterm birth. 13,20 Bacterial culture of the amniotic fluid has been frequently undertaken before placement of emergency cerclage to rule out infection of the amniotic fluid; however, cases of chorioamnionitis and maternal sepsis have occured even when the cultures were negative.…”

“…[14][15][16][17][18][19] It is therefore essential to rule out infection before a cerclage is contemplated. 23 Mass spectrometry-based proteomics is a systems biology technique that can be used to measure numerous protein biomarkers simultaneously, offering a discovery platform to identify predictors of disease and mechanisms of pathogenesis. Traditional methods for determination of intra-amniotic infection, Gram stain, and bacterial culture, lack sensitivity and likely underestimate the prevalence of intrauterine infection in cervical insufficiency.…”

The diagnostic value of fetal fibronectin testing in clinical practice

“…Therefore, cervical length measurement with transvaginal ultrasound could help identifying women at risk for preterm delivery. The clinical cut‐off to define a ‘short’ cervical length has ranged from 15 to 30 mm in existing literature . Women with a cervical length ≤ 15 mm have a high risk of preterm delivery, as 52% of these women deliver within 7 days after measurement .…”

“…The risk of preterm delivery is extremely low if the cervical length is ≥30 mm, with a negative predictive value of 99% (95–100%) . However, there is a lack of compelling evidence for the use of cervical length measurement alone in women with threatened preterm labor . Fetal fibronectin (fFN) as an adjunct to cervical length measurement may improve the prediction of preterm delivery, and might be viable and cost saving .…”