Progesterone is also present without pregnancy. Normally, a woman’s progesterone value varies during a menstrual cycle, during the menstrual phase, follicular phase and luteal phase, and the value will exceed 5ng/ml after ovulation, which mostly indicates the occurrence of ovulation. Progesterone is proof that a woman’s ovaries have the function of secreting progesterone, which is only secreted in elevated levels after ovulation during the menstrual cycle and cannot be used to diagnose pregnancy. Pregnancy is highly suspected only when the chorionic gonadotropin in the blood is elevated. The diagnosis of early pregnancy is confirmed by doubling the chorionic gonadotropin in the blood and by gynecological ultrasound, which shows the growth of a gestational sac and the pulsation of the fetal heart in the uterine cavity. If a woman’s progesterone level is too low after pregnancy, it can easily lead to lower abdominal pain, vaginal bleeding and other cases of preterm miscarriage.