Cervicovaginal fibronectin and cervical length at 23 weeks of gestation: relative risk of early preterm delivery.
OBJECTIVE
To establish the prevalence of cervicovaginal fetal fibronectin positivity at 23 weeks of gestation in a routine population of singleton pregnancies and determine the relative risk of spontaneous delivery before 33 weeks in women with a fibronectin positive result.


METHODS
Prospective clinical study.


METHODS
Inner city antenatal clinic.


METHODS
Singleton pregnancies attending for routine antenatal care.


METHODS
Cervicovaginal fetal fibronectin and cervical length were measured at 23 weeks of gestation. The distribution of fibronectin positivity within subgroups according to maternal characteristics was calculated and the relative risk of spontaneous delivery before 33 weeks was estimated.


METHODS
Prevalence of a fibronectin positive result and its relation to cervical length measurement and spontaneous preterm delivery before 33 weeks.


RESULTS
Of 5,146 women participating in the study, 182 (3.5%) had a fibronectin positive result and 76 (1.5%) had a cervical length of < 15 mm. Fibronectin positive women were more likely to be Afro-Caribbean in origin, to have had a previous second trimester miscarriage and to have a short cervix. In the 5,068 women who were managed expectantly, the significantly independent relative risk of spontaneous delivery at < 33 weeks was 46.2 (95% CI 18.8-113.6), for cervical length of < or = 15 mm, 8.1 (95% CI 3.8-17.5) for a fibronectin positive result, and 4.4 (95% CI 2.2-9.1) for cigarette smoking.


CONCLUSIONS
Fibronectin positivity at 23 weeks of gestation provides useful prediction of pregnancies at risk of spontaneous preterm delivery before 33 weeks, with a relative risk that is twice as high as cigarette smoking, but is a sixth of that of cervical length.
Heath
V C
VC
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, Denmark Hill, UK.
Daskalakis
G
G
Zagaliki
A
A
Carvalho
M
M
Nicolaides
K H
KH
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002584:Cervix Uteri / Q000737:chemistry; D005006:Ethnicity; D005260:Female; D005353:Fibronectins / Q000032:analysis*; D006801:Humans; D007752:Obstetric Labor, Premature / Q000175:diagnosis* / Q000378:metabolism; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D012307:Risk Factors; D002577:Uterine Cervical Diseases / Q000473:pathology*; D014621:Vagina / Q000737:chemistry
D015415:Biomarkers; D005353:Fibronectins