Updated August 12, 2022 | By Jessica Moncivais
A pregnancy test detects human pregnancy hormone to determine whether a woman is pregnant. Women have access to advanced test that can detect pregnancy days before missed periods. Many tests today are marketed as simple and effective, but getting accurate results comes down to when the test is taken.
What is a pregnancy test, and how does it work?
A pregnancy test checks your urine or blood for a hormone called human chorionic gonadotropin (hCG). Your body creates this hormone roughly 6-10 days after a fertilized egg attaches to the wall of your uterus. Levels of hCG will rise quickly after fertilization, doubling every 2 to 3 days during the first 60 days of pregnancy.
When to take a pregnancy test
You can test days before your missed period. Some pregnancy tests can spot hCG 4-5 days before you miss a period.
However, the results will be more accurate if you wait until the first day of a missed period. It is most important to keep track of your menstrual cycle in order to find the best time to start testing. Users who have a negative result with early pregnancy symptoms should retest 48 hours afterwards and/or follow-up with a blood test at the doctor’s office to confirm pregnancy.
We recommend testing in the morning because when there is the least chance of sample dilution. However, if you test later in the day, be sure to reduce liquids a few hours before testing.
Types of pregnancy tests
There are two types of pregnancy tests; one uses a urine sample, the other a sample of blood. Both pregnancy tests detect the presence of the hCG hormone.
Urine pregnancy screening tests can be performed in two different ways and can be performed at home or in a clinic. One way involves collecting your urine sample in a cup and using a test strip to dip into the urine or using a dropper on a cassette. Another option involves placing a test stick into your urine stream and catching your urine in midstream.
The benefit to urine tests is they are non-invasive. No needles! They’re also readily available, offer immediate results, and can be done in the privacy of your home. For most women, they are highly accurate and easy to read.
You get these at your doctor's office, but they’re not used as often as urine tests. Blood tests can determine results earlier than urine tests; doctors can use either qualitative or quantitative tests. Qualitative tests give a simple yes or no answer, while quantitative tests (also known as the beta hGC test) can determine the levels of hCG in the blood and can consequently tell you how far along you are in your pregnancy. These tests can detect pregnancy earlier than a home pregnancy test, about 6 to 8 days after ovulation.
All home pregnancy tests test urine, while health professionals use blood tests. Most women carry out a home urine test before they go to their doctor for a blood test.