Whether a progesterone level of 12 ng/ml is necessary to preserve the fetus depends on the specific situation of the pregnant woman. If the progesterone value is 12ngml for women in the early early days, but when checking the HCG, it is found to be persistently elevated or doubled well, it means that there is a need to preserve the fetus. You can take the medication according to the doctor’s advice, but pay attention to observe whether there is vaginal bleeding, abdominal pain and other uncomfortable symptoms. For women who are 40-50 days pregnant with a progesterone value of 12ng/ml, it means that the value of progesterone is low, and there is the possibility of ectopic pregnancy or embryonic underdevelopment, which needs further HCG examination and combination of ultrasound for specific analysis. If necessary, the patient should be treated with abortion preservation, which can be achieved by taking progesterone capsules or intramuscular injection of progesterone to replenish the body’s progesterone value. Therefore, whether or not to preserve the fetus should be analyzed according to the patient’s specific situation.