If you usually have regular periods, it is recommended to start monitoring on the tenth day of your menstrual cycle. Before monitoring ovulation, it is recommended to have a routine ultrasound to find out if the uterus and both adnexa are normal before monitoring ovulation. If you usually have regular periods, no abnormal vaginal bleeding and are under 30 years old, you can totally try to prepare for pregnancy on your own. Those who have not conceived after one year of preparation are diagnosed as infertile and can be actively tested. Ovulation usually occurs about 14 days before each menstrual period, and the discharge will become thin, stretched and painful in the belly, all of which indicate the imminent ovulation. However, ultrasound monitoring is the most intuitive way to check the development and size of the follicles. An oval or round follicle of 18-20mm is the dominant follicle and should be monitored until it ruptures. Generally, sperm can survive in the body for 72 hours and eggs can survive in the body for 1 day, so intercourse should be arranged both before and after ovulation. Checking the follicles needs to be done dynamically, usually with a visit to the hospital in two to three days.