After the fertilized egg has been deposited, it can usually be tested with a test strip in about 14 days. After the sperm and egg meet, it runs towards the uterus under the action of fallopian tube cilia, and it usually takes about 4-5 days to enter the uterus, search for the location of the bed in the uterus, and then implant in the endometrium to form the bed in 6-7 days after the fertilization, and the trophoblast cells secrete HCG after the bed, and usually you can measure the blood HCG about 7-10 days after the bed to make a clear diagnosis. HCG produced by trophoblast cells gradually increase, about 14 days after implantation, that is, about 20 days after coitus, menstruation overdue about 7 days, you can use test paper to test urine HCG to clarify whether pregnancy. If your period is overdue, it is recommended that you go to the hospital in time to check whether you are pregnant.