Progesterone of 12.6ng/ml after pregnancy may be caused by maternal luteal insufficiency or normal fluctuation, as well as fetal chromosomal abnormality and ectopic pregnancy. If the ultrasound shows that the embryo development is normal, it is possible to keep the pregnancy, and if there is no gestational sac in the uterus or the development of the embryo is not in line with the gestational week, there is not much hope of keeping the pregnancy. Theoretically, progesterone in early pregnancy should be about 25ng/ml. However, in reality, progesterone has a certain degree of volatility, found that the decrease may be a physiological phenomenon. In addition, maternal luteal insufficiency can also lead to low progesterone, but as long as the ultrasound shows that the size of the gestational sac is in line with the gestational week and there is fetal heartbeat and buds, usually avoiding exertion, and giving luteal support when necessary, the hope of preservation is relatively large. In addition to the above reasons, low progesterone may be caused by poor congenital development of the embryo, chromosomal abnormalities or ectopic pregnancy. Poorly developed embryos not only have low progesterone levels, but also have gestational sacs that do not match the actual gestational week, no fetal heart and buds, which are not viable, and the body will reject poorly developed gestational tissues, which can ultimately lead to spontaneous abortion. Patients with ectopic pregnancy usually have progesterone below 15ng/ml, poor doubling of blood HCG, and no gestational sac in the uterus on ultrasound. Most ectopic pregnancies occur in the fallopian tube, and it is impossible to preserve the embryo. With the increase of gestational weeks, the continuous development of the embryo may cause complications such as tubal rupture, internal bleeding and shock. Therefore, if the progesterone is 12.6ng/ml, you should look for the cause, if other tests are normal, you can keep the fetus appropriately, if it is a pathological cause, you have to treat it as soon as possible according to different causes.