Changes in coagulation system during pregnancy have been put forth as risk factors for cerebral venous sinus thrombosis (CVT), yet we still have limited knowledge on markers for predicting the risk of CVT in pregnant women. Therefore, we aimed to investigate the significance of vitamin D (VD) levels and C-reactive protein (CRP)/albumin ratio (CAR), an inflammation marker, as risk factors for CVT in pregnant women. 23 pregnant women who were followed up for CVT, 26 healthy pregnant women who had no pregnancy complications, and 31 non-pregnant fertile women were included in the study. CAR and VD levels were compared between groups. CAR was significantly higher in the pregnant CVT group compared to the other two groups (p < 0.001). CAR was also significantly higher in the healthy pregnant group than the non-pregnant fertile group (p < 0.001). VD levels were determined to be statistically significantly lower in the pregnant CVT group compared to the other two groups (p < 0.001). However, VD levels did not significantly differ between healthy pregnant group and non-pregnant fertile group (p > 0.05). We found no significant correlation between CAR and VD levels in any of the three groups. Pregnant women with CVT were found to have a high rate of severe VD deficiency. Low VD levels and high CAR levels in pregnant women may be associated with an increased risk of CVT.