The best time to check progesterone is mainly at two points in time: first, in the not pregnant during the preparation for pregnancy can be tested on the 2nd-3rd day of menstruation, calculated from the first day of menstrual bleeding, around the 23rd day to test progesterone can determine whether women have luteal insufficiency; second, within the first trimester after the confirmation of pregnancy, testing progesterone can timely find out whether there are problems with the fetus in early pregnancy and whether there is a miscarriage The possibility of miscarriage. Luteinizing hormone is very important for women who plan to get pregnant and during pregnancy, an important hormone that can ensure a smooth pregnancy and childbirth. For women with menstrual disorders and a history of habitual miscarriage, luteinizing hormone testing is especially important. Therefore, there are still some differences in the timing of the progesterone test depending on the purpose of the test, and it is recommended to consult a professional doctor for advice according to your situation.