When progesterone is too low after pregnancy, it may be physiological fluctuation or caused by pathological factors, such as luteal insufficiency, fetal chromosomal abnormality, etc. Therefore, the causes should be identified, and according to the different causes, measures such as observation and follow-up or medication should be taken for treatment. 1. Physiological fluctuation: Progesterone is released in the body in a pulsatile manner, and the concentration of blood can be changed, low progesterone is sometimes physiological, such as blood HCG and ultrasound are normal, there is no vaginal bleeding, abdominal pain and other discomforts can be observed and followed up. 2. Pathologic factors: (1) Luteal insufficiency: maternal luteal insufficiency can cause a decrease in progesterone. Women with luteal insufficiency have symptoms before pregnancy, which can be manifested as shortening of menstrual cycle, and some of them have a history of recurrent miscarriage. If the ultrasound result is normal, which means the embryo is alive, it is recommended to give appropriate progesterone treatment, such as oral progesterone capsules, dydrogesterone tablets and so on. (2) Fetal chromosome abnormality: Fetal chromosome abnormality, development to a certain extent can stop growing, at this time the trophoblast cells will apoptosis, can not stimulate the corpus luteum of pregnancy secretion of progesterone, so the progesterone is low. The patient will also be accompanied by other abnormal test results, such as poor HCG doubling, embryonic development does not match the gestational week. This condition can be treated by waiting for spontaneous abortion, or by suction surgery. Therefore, the cause of low progesterone should be identified and treatment according to the cause is the key. If abortion preservation treatment is needed, you should rest and avoid sexual intercourse during the treatment period, and at the same time, you should have regular checkups to evaluate the treatment effect.