Typically, the first trimester is the first 3 months of pregnancy and the normal range of progesterone is 15-161.4 nmol/L. Progesterone is a hormone necessary to ensure that the pregnancy continues, and is now a gradual rise throughout the pregnancy, increasing as the weeks of pregnancy go by, with the normal values varying from week to week. Different people have different values of progesterone in the third trimester, in general the normal range of values of progesterone should be 15-161.4nmol/L. If the level of progesterone is relatively high, it is less likely to miscarry. Progesterone has the function of promoting the growth and development of the fetus, progesterone is too low it is difficult to maintain a stable uterine environment, will affect the growth of the fetus, the embryo is easy to be rejected by the mother to the yellow pregnancy is difficult to maintain. After a woman is pregnant, she should undergo regular obstetrical examination, which is very important for both the pregnant woman and the fetus. Progesterone abnormalities found during pregnancy, need to follow the doctor’s advice to carry out the appropriate treatment, to avoid accidents, affecting the development of the fetus and the health of the pregnant woman.