A drop in progesterone means that the embryo is underdeveloped and there is a chance that the pregnancy may be terminated or miscarried. When a woman is pregnant, the corpus luteum in her body secretes progesterone, which is an essential hormone for maintaining pregnancy. If a pregnant woman’s corpus luteum is not functioning adequately, it will lead to low progesterone value, which is prone to preeclampsia or miscarriage. However, progesterone value is also related to the quality of the embryo. If the quality of the embryo is not good, the embryo will make self-selection and stop developing on its own. Therefore, if the progesterone value is still decreasing after intramuscular injection of progesterone and abnormalities of fetal heart and gestational sac are found during examination, it may be caused by insufficient luteal function of the pregnant woman or low quality of the embryo, and embryonic arrest or miscarriage will occur. If the progesterone value continues to fall, it means that the effect of keeping the fetus alive is not good, and the pregnant woman should listen to the professional doctor’s advice and terminate the pregnancy if necessary.