Table 2. Regression coefficients, ORs, and 95% CIs of the final combined model^* for predicting SPTD at <32 weeks of gestation.

Predictor	Beta-coefficient	SE	OR (95% CI)	P-value
Cervical dilatation (cm)	0.943	0.262	2.56 (1.53–4.29)	<0.001
Cervicovaginal fluid VDBP (μg/mL)	0.875	0.382	2.39 (1.13–5.07)	0.022
Use of corticosteroid	1.866	0.817	6.46 (1.30–32.03)	0.022
Constant	-3.552	0.937	0.029	<0.001

OR, odds ratio; CI, confidence interval; SPTD, spontaneous preterm delivery; SE, standard error; VDBP, vitamin D binding protein; TIMP, tissue inhibitor of metalloproteinases; DKK, Dickkopf; CVF, cervicovaginal fluid; CRP, C-reactive protein. The formula that was generated to predict SPTD at <32 weeks was as follows: Y = logₑ (Z) = -3.552 + 0.943 × [cervical dilatation (in cm)] + 0.875 × [cervicovaginal fluid VDBP (in μg/mL)] + 1.866 × (1 for use of corticosteroid, 0 for non-use of corticosteroid). Z = e^Y and risk (%) = [(Z / (1+Z)] × 100.

*Final model resulting from a forward regression analysis including the following predictive parameters: VDBP, TIMP-1, and DKK3 in the CVF, serum CRP, cervical dilatation, vaginal progesterone therapy, and use of corticosteroids.