The presence of two bars on the pregnancy test indicates pregnancy, and repeated monitoring is necessary to avoid false positives due to improper handling or expiration of the test strip. The pregnancy test is mainly used to confirm pregnancy by detecting human chorionic gonadotropin in urine. Human chorionic gonadotropin can be detected in blood after the fertilized egg is laid, and with the increase of the hormone content, it can also be detected in urine, which is the usual principle of pregnancy test to check early pregnancy. It can be obviously monitored at about 35 days of gestation, but there are great individual differences, mainly related to the early and late implantation of the fertilized egg. It is recommended that an ultrasound examination be performed after the pregnancy test is clear and completed around 45 days of gestation, mainly to rule out ectopic pregnancy and to get an idea of the embryonic development.