The range of serum progesterone in the first trimester of pregnancy is: 4.73-50.74ng/ml. Progesterone is a hormone produced by the corpus luteum that normally fluctuates with the menstrual cycle. During pregnancy, the level of progesterone will rise gradually with the increase of gestation period. Usually, the progesterone hormone in the early stage of pregnancy mainly comes from the corpus luteum, and in the middle and late stage comes from the secretion of the placenta. Measurement of progesterone is mainly used to determine ovulation, progesterone therapy monitoring and evaluation of early pregnancy status. It is important in determining the functional status of the corpus luteum and in the study of ovarian physiopathology. When the serum progesterone is obviously abnormal, it is necessary to actively consult the doctor and follow the doctor’s instructions for reasonable treatment. Pregnant women during pregnancy should pay attention to do a good job of prenatal checkups, actively listen to the advice of professional doctors to do a good job of comprehensive care and health care, pay attention to rest, at the same time, should relax, to avoid nervousness, anxiety, any discomfort should be timely to the hospital, by the doctor to clarify the diagnosis, and cooperate with the doctor to deal with the symptoms.