HCG is a hormone that starts to be secreted after the fertilized egg is deposited, by checking whether the doubling is good or not, it can determine whether the embryo is healthy or not, but it can’t determine the site of the embryo’s deposit, and any site of the deposit outside the uterine body is known as an ectopic pregnancy, such as the fallopian tubes, uterine horn site, and cervical opening are all considered to be ectopic pregnancies. Ectopic pregnancy is caused by many factors, the most common reason is that the uterine lining is thin or inflammation, etc. is not suitable for bed, the fertilized egg to reach outside the uterus will be ectopic pregnancy, if the embryo is healthy, in the ectopic bed site in the early stages of pregnancy can be nourished by normal development of the embryo. The doubling of HCG checked before 8-10 weeks of pregnancy can be good, normal pregnancy in 8-10 weeks of pregnancy when HCG reaches its peak, after which it will gradually decline, but can not rule out the case of ectopic pregnancy.