γγA progesterone level above 15 nmol/L is considered normal at 4 weeks of pregnancy and preferably above 20 nmol/L. If a low progesterone level occurs, prompt treatment with fetal preservation is indicated.γγAt 4 weeks of pregnancy, the development of the fetus can only be determined by a combination of progesterone and blood HCG values. Ultrasound examination has not yet shown the gestational sac and fetal heart. If the progesterone value is low, do not worry too much, you can take oral progesterone capsules or intramuscular progesterone injection to replenish progesterone, review regularly, and also observe the doubling of blood HCG value. Progesterone is a progesterone secreted by the corpus luteum of the ovary and is necessary for the maintenance of pregnancy after pregnancy. At 4 weeks of pregnancy, the placenta is not fully developed and all progesterone is secreted by the corpus luteum of pregnancy at this time. Progesterone works together with estrogen to reduce the excitability of the uterus, inhibit its activity and ensure normal fetal development. If a low progesterone value occurs in early pregnancy, be alert to the risk of miscarriage. If vaginal bleeding and symptoms such as back pain and abdominal pain occur at the same time, seek medical attention, give exogenous progesterone support and timely fetal preservation treatment. At the same time, pay attention to rest, eat a balanced diet, avoid spicy, stimulating and cold foods, and maintain a good mood.