breakthrough bleeding meaning in Chinese

突破出血
突破性出血

After confirming regular menstruation and ovulation for three months before treatment , patients were examined before and at 4 , 12 , 24 and 48 weeks after treatment began to check for symptom control ( pain , urinary and bowel symptom , breakthrough bleeding )
实验开始前3个月对病人进行月经周期和排卵周期的统计，实验开始后的第4 、 12 、 24和48周检查治疗对症状（疼痛、泌尿系统和肠道系统症状、血量）的改善情况。