Cervical varix is rare and can develop due to various conditions in pregnancy. Most cases of cervical varix during pregnancy are diagnosed in the second or third trimester and are usually associated with abnormal placental location, such as placenta previa or low-lying placenta. A 23-year-old woman with cervical varix bleeding visited our institution at 8 weeks of gestation. This case report describes cervical varix bleeding that developed into a venous thrombus in the first trimester. Ultrasonography with color Doppler and magnetic resonance imaging could be helpful in diagnosis.