The follicle growth rate is about 0.2㎝ per day and will grow to between 1.8-2.5㎝ when ovulation occurs. Generally, if the blood estradiol level reaches 250pg/ml or more, it means that the follicle is mature and of good quality and ovulation will occur under the action of LH peak. If the follicles are always slow to develop and the estradiol level is low, it means that the follicles are not well developed and of poor quality, which affects ovulation. In addition, when a woman is treated with ovulation-promoting drugs she should also pay attention to keeping her mood relaxed and strengthening her body resistance, which also helps to obtain high quality eggs.