The reasons for the decrease of progesterone are various, including insufficient hormones of the mother, disease factors, luteal insufficiency, serious dysfunction of adrenal glands or thyroid gland, and so on. 1. The mother’s own hormone is not enough: the early growth and development of the fetus needs the relative hormone level in the mother’s body, if there is a shortage of the mother’s own hormone secretion, there may be a drop in progesterone, resulting in the cessation of the development of the fetus. 2. Disease factors: ectopic pregnancy, preeclampsia, amenorrhea and other diseases can also lead to a decline in progesterone. 3. Luteal insufficiency: Inadequate luteal function and development of the ovary can also cause a drop in progesterone. 4. Serious dysfunction of the adrenal glands and thyroid gland: The adrenal glands and thyroid gland are the “superiors” that allow the ovaries to produce progesterone. If there is a serious dysfunction of the adrenal glands and the thyroid gland, then the ovaries will become dysfunctional, which will cause a drop in the level of progesterone. If a drop in progesterone occurs, it is recommended to go to a regular hospital for diagnosis and treatment according to the cause.