Not all delayed or stopped periods will come after using progesterone. If a woman has delayed menstruation and does not have a period after 7 days of progesterone withdrawal, she first needs to have a gynecological ultrasound to observe the thickness of the endometrium. If the thickness of the endometrium is more than 1.0cm, but there is no menstruation, the main consideration is that it may be caused by pregnancy or endometrial adhesion or cervical canal adhesion, and further investigation is needed. If there is no menstruation after 7 days of progesterone withdrawal, but the ultrasound suggests that the endometrium is relatively thin, it is considered that there may be endometrial injury, adhesions after endometrial injury, ovarian failure, or hypothalamus, pituitary gland lesions, resulting in abnormal hormone secretion caused by. Because women must have a certain dose of estrogen for progesterone to work, if estrogen is very low or absent, progesterone cannot work.