PROS1 and preterm premature rupture of the membranes: In the logistic regression analysis to predict the probability of PPROM according to the optimal cutoff values, the risk of PPROM was found to be OR (odds ratio) = 6.69 times higher in patients with albumin < 36 g/dL, OR = 8.5 times higher in patients with ferritin > 10.39 ng/mL, OR = 4.66 times higher in patients with ceruloplasmin > 0.44 mg/dL, OR = 3.19 times higher in patients with fibrinogen > 3.74 mg/dL and OR = 3.64 times higher in patients with protein S > 42%.