The Relationships among Various Risk Factors to Predict Early Preterm Birth Compared to Late Preterm Birth

Abstract

Objective: To evaluate and assesse useful factors in predicting early preterm birth (PTB) and determined the increased risks of early PTB for the combinations of these factors compared to late PTB. Methods: The 77 singleton pregnancies with PTL were enrolled. They had undergone examinations including cervical length (CL) and fetal fibronectin (fFN), polymerase chain reaction for sexually transmitted disease, and cervical culture. We first evaluated the statistical significance of the primary predictors (known risk factors before pregnancy) and secondary predictors (fFN, CL, high-sensitivity C-reactive protein [hsCRP] and cervical bacterial analysis). Next, we analyzed the various combinations of meaningful factors. Results: CL <2.5 cm (P=0.007; odds ratio [OR], 3.598), hsCRP ≥0.9 mg/dL (P=0.011; OR, 3.79), and fFN ≥50 ng/mL (P=0.035; OR, 2.75) were more predictive of early PTB than late PTB. The highest OR was observed for the combination of all 3 factors (P=0.039; OR, 7.75). The fFN positivity and hsCRP ≥0.9 mg/dL was in OR 6.094 (P=0.013). The CL<2.5 cm and hsCRP ≥0.9 mg/dL was in OR 5.333 (P=0.009). Finally, the CL <2.5 cm and fFN positivity was in OR 3.946 (P=0.013). The interval between diagnosis and delivery in women with all 3 factors was 8 days shorter than that for women without these factors (P=0.04). Conclusion: Our study is the first to demonstrate the potential risks of PTB using the combination of commonly used in clinical factors, and revealed quantification by the ORs. We will be useful reference value for patients counselling for prediction of early PTB.