hCG is the hormone that pregnancy tests analyzed. The presence or absence of hCG determines whether or not a woman is pregnant. However, this hormone must be above a certain level for the test to detect it.
This is why the pregnancy test should not be taken too early, as hCG levels may still be undetectable. Instead, since the hormone level doubles approximately every 48-72 hours in the first trimester of pregnancy, it is important to wait until the correct time to take the pregnancy test. This would ensure that hCG levels are already high enough to give a reliable result.
Read the full article on: Can pregnancy tests fail? False positives and negatives ( 51).
By Rut Gómez de Segura M.D. (gynecologist), Silvia Azaña Gutiérrez B.Sc., M.Sc. (embryologist) and Cristina Algarra Goosman B.Sc., M.Sc. (psychologist).
Last Update: 10/22/2021