Biochemical markers for the prediction of spontaneous pre-term birth

Objectives: The aim of this study was to identify predictive biochemical markers for preterm labor. Methods: In this prospective study we included 225 asymptomatic Caucasian women consecutively enrolled at 24 weeks of gestation. The following data were collected only once at 24 weeks of gestation: vaginal pH, vaginal fFN, cervical and serum concentration of IL-6, IL-8 and TNFalpha, maternal blood serum, ferritin. Student's t-test, the chi(2)-test and multiple linear regression were used as statistical methods. Results: There were no differences between the age of patients, parity and gestational age at sampling between women who delivered at term and those who delivered preterm < 37 weeks' gestation). There was a significant increase of cervical IL-6 (pre-term 608 +/- 1595 pg/l vs. at term 58.9 +/- 112 pg/l) and serum ferritin (pre-term mu g/l 74.4 +/- 1.1 vs. at term 26.3 +/- 56.5 mu g/l) in pregnant women who delivered pre-term (P<0.05). No differences in cervical IL-8 and cervical TNFalpha between pre-term and term deliveries were found. Multiple linear regression confirmed that the vaginal pH value and cervical fFN test were the best predictive biochemical markers of pre-term birth (standardized coefficient Beta=0.33 and 0.22, respectively). Conclusions: In order to evaluate pregnancies for pre-term labor, the presence of pH>4.5 and a positive fFN test seems to be predictive of subsequent pre-term delivery. (C) 2002 International Federation of Gynecology and Obstetrics. Published by Elsevier Science Ireland Ltd. All rights reserved.