There are several procedures to promote ovulation with letrozole: 1. first, laboratory tests are done to understand ovarian function and whether estradiol is normal. 2. if all the above tests are normal, you can take letrozole to promote ovulation. 3. start taking it orally on the 5th day of menstruation for 5 days, and monitor the growth and development of the follicles by ultrasound, and guide intercourse after the follicles reach a dominant diameter, which will increase the chance of pregnancy. This will improve the chances of pregnancy. The success rate of letrozole ovulation promotion is still relatively high, the success rate of ovulation promotion is about 90%, during the period of taking letrozole ovulation promotion, you must observe whether there is ovarian hyperstimulation, and also to prevent premature ovarian failure.