Cerebral venous thrombosis (CVT) is a rarely encountered cerebrovascular disease. The incidence of CVT associated with pregnancy or the puerperium is not exactly known. It is thought that only small proportion of patients develop CVT during pregnancy, and most of them occur during puerperium or in the last trimester of pregnancy. The presence of pregnancy itself is a predisposing factor for thrombosis associated with the hypercoagulable state. However, additional various etiologies may be determined for CVT during pregnancy. Here, we present a women with CVT during the first trimester of her pregnancy with additional risk factors of MTHFR C677 T heterozygote mutation, protein S deficiency, and activated protein C resistance. We want to emphasize that additional various etiologies may be determined for CVT during pregnancy and this is important during establishing the long-term follow-up and treatment of the patient.