Pregnancy tests work by detecting a hormone known as human Chorionic Gonadotrophin (hCG). The amount of this hormone increases steadily over the first few weeks of pregnancy, peaking at seven to twelve weeks. Home pregnancy kits test the urine for this hormone.
When trying to conceive or checking for peace of mind, a pregnancy test can be very accurate and simple. All Clearblue pregnancy tests are over 99% accurate when used from the day your period is due.