A pregnancy test can tell whether you are pregnant by checking for a particular hormone in

your urine or blood. The hormone is called human chorionic gonadotropin (HCG). HCG is

made in a woman's placenta after a fertilized egg implants in the uterus. It is normally made

only during pregnancy. A urine pregnancy test can find the HCG hormone about a week after

you've missed a period. The test can be done in a health care provider's office or with a home

test kit. These tests are basically the same, so many women choose to use a home pregnancy

test before calling a provider. When used correctly, home pregnancy tests are 97–99 percent

accurate.