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.
LaShay
N
N
Department of Obstetrics and Gynecology, University of New Mexico Health Science Center, Albuquerque.
Gilson
G
G
Joffe
G
G
Qualls
C
C
Curet
L
L
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