How do Pregnancy Tests Work?

Pregnancy tests detect the presence of a hormone that the body starts producing at the moment the fertilized egg implants into the uterine wall.

The presence of hormones is therefore a clear indication that a woman is pregnant.

There are two types of pregnancy tests. One detects hormone in the blood, and the other detects hormone in the urine.

Blood pregnancy tests are generally performed by health care professionals in clinics or doctors’ offices, while urine tests don’t require the presence of a medical professional and can be easily performed privately at home.

Another major difference between the tests is that while urine tests can only verify the presence of the hormone and therefore return just a yes or no answer, 

blood tests can provide more detailed information. For example, by measuring the amount of hormone in the blood it is possible to pinpoint the moment of conception or the very beginning of the pregnancy fairly accurately.