We often get questions via Facebook Messenger asking if they're pregnant or not (even though it's a question we cannot answer). There are early signs of pregnancy, but the quickest way to know for sure is to take a home pregnancy test. It detects levels of human chorionic gonadotropin (hCG), a hormone produced by a developing placenta. It's inexpensive and easy to do: Just pee and wait for the results.
But how accurate are home pregnancy tests? According to Heidi Murkoff and Sharon Mazel, authors of What To Expect When You're Expecting, once an embryo begins implanting itself in the uterus, between six to 12 days after fertilization, hCG can already be detected in the blood and urine. It is possible, however, that some home pregnancy tests may not be able to catch hCG yet a week after conception.
Taking the test too early, like before your scheduled period, may lead to a false negative result. So it is perhaps better to take it a few days after your period's due date. A false positive result, on the other hand, is less common. "The only way your body can have hCG running through it is if you're pregnant. If your test is showing a line, no matter how faint it is, you're pregnant," wrote Murkoff and Mazel.
The faint line may be due to the sensitivity of the pregnancy home test. Check the pregnancy home test's milli-international units per liter (mIU/L); the lower the mIU number, the more sensitive. For example, a pregnancy home test with a sensitivity of 20mIU/L can detect hCG better that a pregnancy home test with 50mIU/L sensitivity. Remember this when choosing a home pregnancy test kit.
The key to the accuracy of home pregnancy tests is when to take it. You should at least wait after your missed scheduled menstruation before taking the test. Some tests promise to detect hCG a day after your missed period. But you should wait a week or 10 days after your missed scheduled menstrual period to take the test.
For more accurate results, follow the steps of the home pregnancy test kit to the letter. Many pregnancy tests available here often include instructions such as laying the test kit on a flat surface and then waiting for a drop of urine to get absorbed before adding another drop. Many women are recommended to use their first pee of the day to get a more accurate result, but it's not necessary.
Still, no matter how many positive home pregnancy tests you take, you still need to go to your doctor to confirm your pregnancy. A pregnancy blood test is more accurate than a home pregnancy test. One of the benefits of testing early is your doctor can give your prenatal vitamins, and you can start on your prenatal care early.
If you've tested negative on several home pregnancy tests, but your period still hasn't arrived, a consultation with your ob-gyn is still a must.