In clinical practice, the majority of women have a menstrual cycle of 28-30 days, and some have different menstrual cycles due to individual differences. Some may have a menstrual cycle of 35 or 38 days, which is normal, while others may have a quarterly menstrual cycle, which is also known as quarterly menstruation. Ovulation is often sporadic in such patients, because ovulation is relatively rare, the chance of pregnancy is relatively lower. It is recommended that such women should have blood tests for sex hormones on the second or third day of their menstruation to find out whether the endocrine secretion is normal, and then to find out whether the ovulation function is normal or not.