Biochemical markers for the prediction of spontaneous pre-term birth

The aim of this study was to identify predictive biochemical markers for preterm labor.

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.

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 pre-term (<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 microg/l 74.4+/-1.1 vs. at term 26.3+/-56.5 microg/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).

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.