After the sperm and egg unite to form a fertilized egg, the human chorionic gonadotropin is secreted on the sixth day. The early pregnancy test is to check the level of this hormone in the urine to determine if you are pregnant. It is recommended to buy test strips half a month after sexual intercourse, the test strips show two bars for pregnant women and one bar for those who are not pregnant, the accuracy rate is about 85% or more, those who are negative can be rechecked in a few days. Because the sperm survival time is 2-3 days, pregnancy is not necessarily immediate after sex, and then there are differences in hormone secretion after pregnancy. Early pregnancy test paper is very simple and convenient, but it is affected by many factors, such as taking urine, the use of test paper can produce errors, the late arrival of menstruation after sexual intercourse occurs, if necessary, go to the hospital for blood test or ultrasound examination to confirm the diagnosis, so as not to delay the treatment.