The absence of menstrual flow in women after three days of oral progesterone is actually a normal phenomenon and there is no need to be anxious. Because progesterone can promote endometrial interstitial hyperplasia, during the period of oral medication, there is a certain level of progesterone in the body, which will not cause endometrial exfoliation. At this time, you can continue to take progesterone orally for five days, and then stop the medication. After the progesterone level in the body suddenly drops, the endometrium loses the support of progesterone, and only then will the exfoliation occur. There is another situation, such as when a woman’s estrogen level is low, in which case she will not get her period after taking progesterone orally. There is also the case when a woman is already pregnant and the endometrium has already metastasized, which will not cause menstruation no matter how long she takes progesterone.