The normal value of progesterone in the sixth week of pregnancy is 20-32ng/ml, if the value is low, it may affect the normal development of embryo and lead to miscarriage. Progesterone is a progesterone, which is secreted by the corpus luteum of ovary in the early stage of pregnancy, and the initial secretion is not very large. In the early stage of pregnancy, progesterone is secreted by the corpus luteum, and the initial secretion is not very large. After two months of pregnancy, the placenta gradually forms and begins to secrete progesterone, and the placenta has not yet formed in the sixth week of pregnancy. The main function of progesterone is to inhibit the contraction of uterine smooth muscle, stabilize the endometrium, avoid embryo rejection by the body’s immune system, and at the same time, it can promote the development of breast tissue. If the value of progesterone is low, it is easy to have contraction or rejection reaction to affect the stability of embryo and make the embryo be expelled from the body.