Fertility preserving progesterone intramuscular injection will be more effective than oral, according to the individual circumstances of preterm miscarriage, to choose oral or intramuscular treatment. Intramuscular progesterone does not go through the first-pass effect of the liver, most of the drugs injected directly into the blood circulation after the action, the effect will be more stable. Oral progesterone enters the digestive tract through the liver detoxification, detoxification at the same time reduce the efficacy of the drug, oral progesterone is more unstable. After pregnancy progesterone is only slightly low, no other obvious symptoms, and more afraid of pain women can oral progesterone, oral progesterone is generally slower than intramuscular injection absorption. After pregnancy progesterone is particularly low, combined with vaginal bleeding, oral progesterone gastrointestinal reaction is more sensitive, this kind of women can intramuscular injection of progesterone to treat, after the injection drug absorption is better, conducive to preservation of the fetus treatment. It is recommended that women use progesterone to treat their pregnancy under the guidance of a doctor, who will decide on the way to administer the drug according to the individual’s situation.