Pregnancy tests date back to 1350 BC, where the ancient Egyptians found a way to conduct a test with a mind-blowing 70% accuracy. How they did it was by urinating on both wheat and barley seeds, and if one of them sprouted within a certain amount of time, you're pregnant!
The reason for this is because a pregnant woman has more estrogen in their urine, which speeds up the growing process in certain hops.
Modern pregnancy tests are far more accurate and give results within minutes, so how do they work?
All variants of pregnancy tests are designed to detect one thing, the presence of a hormone called HCG. HCG is produced by a woman in the earliest stages of pregnancy, it is responsible for the prevention of further ovulation and formation of the placenta.
The test process starts when urine is applied to the exposed strip at the end of the test. The strip is highly absorbent and carries the urine through 3 separate zones.
These zones are:
- The Reaction Zone: Y shaped proteins called antibodies merge with HCG hormones. These antibodies carry an enzyme that is reactive to coloured dye.
- The Test Zone: The urine carries on being absorbed by the test strip and goes further up to a new zone where more Y antibodies are present. The abundance of these antibodies will merge with HCG and remain at the same spot on the test strip. Once these molecules bind, it triggers the enzymes to amalgamate with the coloured dye which shows a line in the test result.
- The Control Zone: The last and final zone is exactly the same as the Test Zone. However, it serves as a confirmation or "double-check" zone, which increases the test's accuracy. If both coloured dye lines show, chances are that you are pregnant.
Take a look at the video below by the YouTube channel, TED-Ed, on How Do Pregnancy Tests Work?...