refers to the alteration of normal bacterial flora of the vagina,
in which normal lactobacilli are replaced by anerobic
organisms. BV may be present in up to 10-25% of pregnant
women 18 and up to 64% of women attending sexually
transmitted diseases (STD) clinic. Half of these women with
BV are asymptomatic. An association has been found between
BV and preterm labor and it has been found to increase the
risk of preterm labor by two-fold 19. However, many studies
have been done in mixed populations disregarding the fact
that BV is more common in Afro-Caribbean than in white
women. Results have been largely inconclusive and the benefit
of screening for BV with the aim of predicting the onset
of preterm labor is still unclear especially in low risk
community 20.
Screening for fetal fibronectin (fFN)
Fetal fibronectin (fFN) is a basement membrane protein
produced by the fetal membranes and functions as an
‘adhesion binder’. It facilitates the attachment of the placenta
and membranes to the uterine decidua and is normally
detectable in cervical secretions until 16-20 weeks of gestation.
Appearance of fFN in cervical secretions after 24 weeks of
gestation may indicate disruption of the normal adhesion
between chorioamnion and the underlying decidua. Hence, it
may be a marker of inflammation of the fetal membrane /
decidual inter-phase, with or without infection, that often
heralds the onset of preterm labor. Many studies have shown
an increased risk of preterm birth, if fFN is positive after 24
weeks and decreased risk if this protein is negative in cervical
secretion. A meta-analysis of 40 studies revealed a very high
negative predictive value for fFN in predicting the onset of
preterm birth in the next 3 weeks 21.
The specificity of fFN test for predicting preterm delivery
within 1 and 2 weeks was 89%, whereas for delivery within
3 weeks it was 92%. The sensitivity of the test in predicting
the onset of preterm labor within 1 week and 3 weeks was
71% and 59%, respectively 21.
It appears that a negative fFN test is useful in ruling out an
imminent preterm delivery, whereas the implication of a
positive test is uncertain. It can be recommended in highrisk
women who fulfill the criteria of intact membranes,
minimal cervical dilatation (