Early pregnancy, the first 12 weeks of pregnancy, is a critical period for embryo formation. A number of mothers-to-be show signs of preterm abortion such as vaginal bleeding and lower abdominal pain, which is not uncommon and can account for up to 30% of all pregnancies, and nearly half of which will result in miscarriage. Therefore, bleeding during early pregnancy should not be taken lightly. Miscarriage is a common complication of pregnancy, especially in early pregnancy, accounting for 10-15% of all pregnancies, with early pregnancy (i.e., within 12 weeks of gestation) accounting for more than 80% of all miscarriages. The causes of miscarriage are complex, among which embryonic chromosomal abnormalities are the main cause of miscarriage, accounting for 50-60% of early spontaneous abortions. Other causes of miscarriage include high fever, infection by certain viruses or protozoa, ischemia and hypoxia due to severe maternal systemic diseases, abnormal thyroid function, abnormally high blood glucose due to severe diabetes, luteal insufficiency, miscarriage due to immune factors, uterine malformation and fibroids affecting embryo implantation, cervical insufficiency, trauma, excessive smoking, alcoholism, drug abuse, environmental factors, etc., and also Some miscarriages are of unknown origin. If there are signs of preterm miscarriage, you should seek medical help. The doctor will usually ask for medical history, such as any diabetes, thyroid disorders, immune disorders, uterine malformations, etc., as well as any previous history of spontaneous miscarriage, exposure to harmful substances or environment during pregnancy, etc. These can help the doctor look for possible clues to trigger the miscarriage, but unfortunately in most cases no definite cause can be found. Doctors also recommend that pregnant women have their progesterone levels checked because they are associated with a good or bad embryo and because they can also detect luteal insufficiency. Progesterone, also known as progesterone, plays a very crucial role in regulating the menstrual cycle, embryo implantation and maintaining pregnancy. Progesterone in early pregnancy is mainly secreted by the ovarian corpus luteum, which reduces smooth muscle excitability and inhibits uterine contractions. In addition, progesterone regulates the immune response, inhibits the maternal immune rejection of the embryo, a foreign body, and facilitates the growth and development of the embryo in utero, thus progesterone plays a key role in maintaining pregnancy in several ways. In animals, progesterone levels will induce labor if reduced in late gestation. In humans, progesterone is essential for the maintenance of early pregnancy. If the ovaries or ovarian corpus luteum are removed during early pregnancy for various reasons, this will result in miscarriage. If progesterone antagonists, such as mifepristone, are used during pregnancy, they will also lead to miscarriage, which is the main mechanism of medication abortion. Therefore, if a preterm abortion occurs, the application of progesterone for fetal preservation may decrease the sensitivity of the uterus, reduce bleeding and inhibit uterine contractions, and may be effective for preterm abortion due to certain causes (e.g., luteal insufficiency, high uterine sensitivity). However, since spontaneous miscarriage is many times due to problems with the embryo itself and miscarriage is a natural elimination of a bad embryo, progesterone for fetal preservation is not always successful. Most of the progestins currently used for fetal preservation are natural progesterone, which has not been found to be teratogenic to the embryo. The routes of progesterone supplementation include: intramuscular, oral, and vaginal administration. The disadvantage of intramuscular injection is the pain at the injection site and the possibility of infection and abscess at the injection site; in oral administration, the drug is absorbed through the intestine and passes through the liver first, and since the liver metabolizes most of the drug (also called liver first pass effect), the real effect of the drug is only a small part of the drug, so the oral dose is large and has the side effect of causing dizziness and drowsiness The vaginal dose is mainly micronized progesterone, which is absorbed vaginally and first passes through the uterus, resulting in a higher local concentration in the uterus and fewer systemic side effects. Sometimes pregnant women do not have signs of preterm abortion, but blood tests reveal low progesterone values. In fact, while high progesterone certainly reflects normal embryonic development, there are some normal embryos with low progesterone, and the systemic progesterone concentration does not necessarily accurately reflect the local progesterone concentration in the uterus, so progesterone treatment for these pregnant women to preserve the pregnancy is more comforting, although it does not exclude the effect that it may be useful. Therefore, for mothers-to-be with signs of pre-eclampsia, they should treat the miscarriage with the right attitude. It is good to keep the fetus, but don’t blame each other or blame yourself if you can’t, and believe that most people can eventually get a healthy baby.