Biomarkers for the prediction of preterm delivery.

This structured review discusses the current literature on selected biomarkers and their ability to predict preterm delivery (PTD). Among symptomatic women, the likelihood ratio (LR+) for the prediction of PTD was found to be greater than 10 using amniotic fluid (AF) interleukin-6 (IL-6), AF Ureaplasma urealyticum, as well as a multi-marker consisting of cervical IL-6, cervical IL-8, and cervical length (CL). The LR+ was found to be between 5 and 10 for serum C-reactive protein (CRP). An LR+ between 2.5 and 5 was recorded for serum corticotropin-releasing hormone (CRH), cervical fetal fibronectin (fFN), cervical IL-6, serum relaxin, and a multi-marker consisting of fFN and CL. CL and bacterial vaginosis (BV) both predicted PTD in women with preterm labor with an LR+ of less than 2.5. In asymptomatic women, AF U. urealyticum and a multimarker consisting of five individual markers [fFN, CL, serum alpha-fetoprotein (AFP), serum alkaline phosphatase, and serum granulocyte colony-stimulating factor (G-CSF)] predicted PTD with an LR+ greater than 10. The LR+ was between 5 and 10 for serum relaxin and CL. LRs+ recorded for serum alkaline phosphatase, salivary estriol, serum CRH, serum G-CSF, cervical IL-6, AF IL-6, cervical fFN, AFP, and Chlamydia all ranged between 2.5 and 5. Finally, an LR+ below 2.5 has been documented for serum ferritin, serum CRP, BV, and cervical ferritin.