Chorionic gonadotropin can be detected in the blood 2-3 days after the fertilized egg has been laid, and the pregnant woman can determine whether she is pregnant by taking a blood test. It takes about 1 week for the fertilized egg to settle, and on the 6th day of fertilization, the syncytial trophoblast begins to secrete trace amounts of HCG. 10 days after fertilization, i.e. about 2-3 days after the fertilized egg settles, the pregnancy can be detected by measuring HCG in the blood. When HCG is detected above 5 U/L, pregnancy is indicated. The pregnancy can also be detected by morning urine test, such as a morning pregnancy test or a pregnancy test, about 10 days after the fertilization of the egg. However, it is important to note that HCG testing cannot determine whether the pregnancy is intrauterine or ectopic, and ectopic pregnancy can be ruled out by ultrasound examination after about 6-8 weeks of pregnancy, counting from the first day of the last menstrual period. In addition, in addition to the HCG and progesterone tests, the development of the embryo should be determined by gynecological ultrasound.