Some of the common reasons why embryos do not implant are factors such as the endometrium being too thin, abnormal hormone levels in the body, and ectopic pregnancies. Failure of the embryo to successfully implant is one of the causes of infertility. The endometrium is less than 0.8 centimeters thick, and the gestational sac has difficulty in implanting or miscarriage occurs. Low levels of progesterone in the body during the embryo’s implantation period also tend to make implantation difficult, leading to biochemical pregnancy. Inflammation of the fallopian tube or other causes of tubal incompatibility, the gestational sac can not reach the normal uterine cavity, ectopic pregnancy will occur, resulting in the embryo can not be normal bed. Those with infertility and multiple biochemical pregnancies are advised to go to the hospital for a thorough examination.