PROS1 and hepatitis B virus infection: A structured questionnaire was used to obtain sociodemographic, obstetric, and clinical data from each participant.<h4>Results</h4>Levels of albumin, fibrinogen (4.09 [3.57-5.94] vs. 6.89 [5.43-9.08], <i>p</i> < 0.0001), protein C (2.46 [1.09-3.42] vs. 4.12 [2.96-6.07], <i>p</i> < 0.0001), and protein S (2.61 [2.20-3.36] vs. 2.98 [2.53-3.54], <i>p</i> = 0.036) were significantly reduced in the hepatitis B-positive pregnant women than the negative controls.