Symptoms of low progesterone in women, usually manifested as luteal insufficiency, the most common symptom is premenstrual bleeding, which starts to bleed in small amounts a few days or even a week or so before the normal menstrual flow and continues until the normal menstrual flow, and belongs to the type of bleeding with luteal insufficiency, also known as luteal phase defect, which means that the function of the corpus luteum formed by the follicle after ovulation is not as good as the secretion of progesterone, that is, insufficient progesterone, or the corpus luteum premature degeneration, resulting in reduced endometrial secretion responsiveness. Clinically, it is characterized by delayed development of the endometrium during the secretory phase, and the development of the endometrium is not synchronized with the development of the pregnant egg, which may manifest as easy miscarriage after pregnancy, or even infertility, manifested by shortened menstrual cycles, frequent menstruation, and generally menstrual cycles of less than 21 days.