In daily life, for early pregnancy with a small amount of vaginal bleeding, especially for pregnant women who have difficulty conceiving and IVF pregnancy is hard to come by, once the signs of pre-eclampsia miscarriage appear, it is like a great enemy, desperately using various measures to protect the fetus in all aspects, progesterone doses are added again and again, pregnant women and their families are doubly stressed and anxious. When the pregnancy persists, they think they have the right method and spread the word among their friends, but when the miscarriage finally occurs, they will find various reasons to regret it. Is it true that miscarriage can be preserved? Is the child that is “preserved” necessarily good? We know that in early pregnancy, the progesterone and estrogen secreted by the corpus luteum of pregnancy on the ovary maintain pregnancy by supporting the uterine meconium and reducing the sensitivity of the smooth muscle of the uterus and inhibiting uterine contraction. Progesterone also has an immune effect and can directly participate in the immune response at the maternal-fetal interface, promoting maternal-fetal tolerance and preventing miscarriage. In the luteal phase of pregnancy, the placenta replaces the corpus luteum in the production of estrogen and progesterone at 7-9 weeks of gestation, thus realizing the functional transition and handover between the corpus luteum and the placenta. Therefore, people worry that the luteal phase cannot have enough progesterone to protect the pregnancy and will routinely apply progesterone to preserve the pregnancy. In fact, except for IVF, the amount of progesterone needed to maintain pregnancy during early pregnancy is very small. Whether conceived naturally or by ovulation promotion line assisted reproduction treatment, 20-30% of the population will have symptoms of aura miscarriage such as a small amount of vaginal bleeding in early pregnancy, and 10-20% will have miscarriage, of which only a very small percentage of the population has normal embryonic chromosomes and miscarriage is caused by maternal luteal insufficiency, and the efficacy of luteal support treatment for these patients is obvious; from a genetic point of view, at least 50% of miscarriages are caused by embryonic factors. The miscarriage is caused by embryonic factors, i.e. the embryo is abnormal and the miscarriage is a natural elimination process, such miscarriage is not effective with progesterone treatment, but can only delay the miscarriage. Even if such an abnormal embryo is successfully preserved for preterm abortion, the risk of various malformations of the born fetus is high, which brings a heavy burden to both the family and the society. The need for progestogen supplementation for preterm miscarriage is controversial internationally, and there is no sufficient evidence to support that progestogen supplementation can reduce the chance of eventual miscarriage. Also even if progesterone support is effective, according to the natural rule, progesterone use up to 70 days of pregnancy can be gradually reduced to allow the placenta to take over the function of the gestational corpus luteum, rather than the longer the progesterone is used, or the more progesterone is used, the better.