Will cervicovaginal interleukin-6 combined with fetal fibronectin testing improve the prediction of preterm delivery?
OBJECTIVE
We sought to investigate if determination of cervicovaginal interleukin-6 (IL-6) levels would enhance the positive predictive value of fetal fibronectin (fFN) for preterm birth.


METHODS
A prospective cohort study was undertaken of 135 women between 24 and 34 weeks gestation with symptoms of suspected preterm labor. Cervicovaginal secretions were collected for both IL-6 and fFN and measured by immunoassay and ELISA, respectively. Outcome variables included preterm delivery in less than 48 h, within 7 days, and prior to 37 weeks. Statistical analysis was performed with Fisher's exact test, regression for logarithmic transform levels, and multivariate logistic regression. ROC curves were created for IL-6 levels.


RESULTS
IL-6 and fFN levels were both elevated in cervicovaginal secretions of women with symptoms of preterm labor. IL-6 values >100 pg/ml resulted in a odds ratio for delivery at <37 weeks of 1.57 (95%CI=0.89-2.75, P=.11), whereas fFN values >50 ng/ml resulted in a preterm delivery risk of 4.58 (95%CI=1.54-13.35, P=.003). Combining IL-6 and fFN results did not improve upon the predictive value of fFN alone for preterm birth [odds ratio 4.00 (95%CI=1.31-12.17, P=.015)].


CONCLUSIONS
Cervicovaginal IL-6 levels did not provide any additional, independent effect on the prediction of preterm birth beyond that of fFN testing alone.
Department of Obstetrics and Gynecology, University of New Mexico Health Science Center, Albuquerque.
N
N
LaShay
G
G
Gilson
G
G
Joffe
C
C
Qualls
L
L
Curet
D002584:Cervix Uteri / Q000378:metabolism*; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005353:Fibronectins; D005865:Gestational Age; D006023:Glycoproteins / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D007118:Immunoassay; D015850:Interleukin-6 / Q000032:analysis* / Q000378:metabolism; D016015:Logistic Models; D011247:Pregnancy; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014621:Vagina / Q000378:metabolism*
C403421:FFN protein, human; D005353:Fibronectins; D006023:Glycoproteins; D015850:Interleukin-6