Consider taking a pregnancy test approximately 4 weeks after the first day of your last menstrual period (LMP).
What Do Pregnancy Tests Measure?
Pregnancy tests turn positive when the pregnancy hormone, human chorionic gonadotropin (hCG), shows up in the urine (the pee on the stick).
Insider Info: The developing placenta starts producing hCG roughly 4 days after the fertilized egg implants in the lining of the uterus. FYI: the placenta is an organ that forms during pregnancy and provides the fetus with oxygen and nutrients.
Double Take:
- You can get a false negative pregnancy test (i.e. a negative test even though you’re pregnant) if you take the test too soon. If you get a negative result, but you haven’t gotten your period and you’re experiencing pregnancy symptoms, take another test.
- False positives (when the test is positive, but you’re not pregnant) are possible as well, but they’re much less common.
Blast From the Past:
Did You Know The First Pregnancy Tests (From the 1930s) Were Done in a NOT Very PETA-Friendly Way?
Tell Me More:
If a woman was thought to be pregnant, her urine was injected into a female rabbit. The rabbit was then surgically opened (read: killed) to see whether its ovaries had enlarged due to the presence of the hCG pregnancy hormone. If so, the pregnancy test (the “rabbit test”) was considered positive.
PediaTrivia:
The band Aerosmith randomly references this practice in their song “Sweet Emotion” with the lyric “the rabbit done died.” Hopefully this tidbit will be a final Jeopardy question that you can crush one day!1
