The duration of progesterone injection for fetus preservation varies from person to person, and in general, it does not exceed two weeks. Progesterone injection belongs to the progesterone class of drugs, which can promote the endometrial lining from the proliferative phase to the secretory phase, and can be used clinically for the treatment of fetal preservation. If progesterone is relatively low in early pregnancy, progesterone injections need to be taken under the guidance of a doctor. The progesterone level should be monitored during the treatment period and the injection can be stopped when the progesterone level is within the normal range. If the embryonic development is still stagnant after two weeks of fertility preservation treatment, and the blood HCG level is abnormal without any effect, termination of pregnancy can be considered. In addition, the application of progesterone injection for fetal preservation treatment to normalize progesterone cannot be stopped immediately, and oral drospirenone tablets are needed for consolidation treatment. Pregnant women should take rest and refrain from sexual intercourse while undergoing fetal preservation treatment.