Fetal Fibronectin Test Accuracy for Predicting Preterm Birth Risk | InformativeBD

Maysoon Sharief, and Saha Mahmood, from the different institute of the  Iraq. wrote a research article about, Fetal Fibronectin Test Accuracy for Predicting Preterm Birth Risk, entitled, Accuracy of cervico vaginal fetal fibronectin test in predicting risk of spontaneous preterm birth. This research paper published by the International Journal of Biomolecules and Biomedicine | IJBB. an open access scholarly research journal on Biomedicine, under the affiliation of the International Network For Natural Sciences | INNSpub. an open access multidisciplinary research journal publisher.

Abstract

Preterm delivery is the leading cause of neonatal mortality. One of the best predictors to assess the risk of preterm labour (PTB) is by measuring fetal fibronectin (fFN) in cervico vaginal secretion after 26 weeks of pregnancy. The aim is to evaluate the diagnostic accuracy of qualitative cervico vaginal fFN in symptomatic women and asymptomatic high risk women during antenatal care. Prospective study which was conducted in Basrah Maternity and Child Hospital. It included 106 pregnant women at gestational age more than 26 weeks who had uterine contraction with or without pervious risk factors for PTB. Cervico vaginal fluid sampling was undertaken from all women included in the study after the age of 26 weeks of gestation and qualitative fFN assessment was done with 50ng/ml is the cut off point for positivity. As regard qualitative fFN assessment for predicting of PTB sensitivity, specificity, PPV, NPV, were 71%, 87%, 40.50%, 94% respectively in symptomatic women. While in asymptomatic women with previous high risk had 26% sensitivity, 84% specificity, 32% PPV, and 87% NPV. Qualitative assessment of fFN in cervico vaginal fluid is good predictive marker in detecting of PTB.

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Introduction

Preterm labour is defined as regular contractions of the uterus starting before 37 weeks of pregnancy that result in cervical effacement and dilatation. Globally, about 15 million babies are born preterm each year. The incidence of preterm birth varies significantly across the globe (American College of Obstetricians and Gynecologists, 2016).

Approximately 30-35% of preterm birth PTB are iatrogenic due to medical or obstetric complications, 40-45% are related to spontaneous preterm labour, and 25-30% to preterm rupture of membrane. Spontaneous pre-term birth is most commonly caused by pre-term labour in caucasians, and preterm prelabour rupture of membrane in black women indicating the existence of potentially different causative mechanism (Offiah et al., 2012).

Fetal fibronectin is a glycoprotein variant of fibronectin family present in amniotic fluid, placenta and the extracelluar substance of the decidua (Bennett, 2018). Its synthesis and release is increased by the mechanical and inflammatory events which occur prior to the onset of labour (Bennett, 2018). Fibronectin is often described as "leaking" from disruption to the fetal membranes and decidua in the lower pole of the uterus associated with early biochemical events of parturition. 

However, it is also an inflammatory response gene, and therefore concentrations of fibronectin in vaginal fluid can be considered to also be marker of inflammation (which may be pathological or a normal part of the onset of labour at term) (Bennett, 2018).

Fetal fibronectin may normally be detected in vaginal secretions at levels in excess of 50ng/ml. However, it is now being increasingly used to predict risk in women who are asymptomatic but at risk for other reasons, in particular cervical shortening (Foster and Shennan, 2014; Kuhrt et al., 2016). 

Since fFT is present in amniotic fluid and placental tissue, mechanical or inflammatory-mediated damage to the membranes before PTB might result in its release into the cervix and vagina (Honest et al., 2002).

The presence of cervico vaginal fFT in the second and third trimesters of pregnancy identifies a subgroup of women who are at high risk for PTB. This phenomenon may reflect the separation of the chorion from the decidual layer of the uterus, with the release of intact or degraded chorionic components of the extracellular matrix into cervical and vaginal secretions (Lockwood et al., 1991). Thus, early detection of PTB is difficult because initial symptoms are often mild and may occur in normal pregnancies.

Even an interesting works, mostly in USA, have been carried out among different population (Lockwood et al., 1991; Honest et al., 2002; Imas, 2003; Hezelgrave et al., 2015; American College of Obstetrics and Gynecologists, 2016; Bennett, 2018) but unfortunately, there is no work which has been done among women in our region. Thus, it is of value to know its accuracy, sensitivity and specificity in predicting spontaneous PTB in women with or without symptoms. It is expecting to use the results of this study to predict and diagnose PTB. In addition, the usual treatment in clinical practice depends on accurate prediction of spontaneous PTB.

Reference

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American College of Obstetricians and Gynecologists. Preterm (premature) labour and birth[Internet]. Washington, DC: American College of Obstetricians and Gynecologists; 2016 [cited 2018 August13]. Available from: http://www. acog.org/Patients/FAQs/Preterm-Premature-Labor

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