Taking a pregnancy test can be filled with excitement for some people, whereas for others it may be a little intimidating. Before you take a pregnancy test, you might check to see if you are experiencing any pregnancy symptoms. A missed menstrual cycle is the most common symptom leading a woman to take a pregnancy test.
How does a test tell if you are pregnant or not?
A pregnancy test detects the presence of a hormone called human chorionic gonadotropin (hCG) in your blood or in your urine. hCG is produced in the placenta shortly after the embryo attaches to the uterine lining and builds up rapidly in your body in the first few days of pregnancy.
How long do I have to wait before I take a test?
Most doctors recommend that you wait until the first day of your missed period before
taking a home pregnancy test. A missed period is usually one of the first signs of pregnancy. This is usually around two weeks after conception.
However, some tests are more sensitive than others and can be taken earlier. Concentrations of hCG are reported in milliInternational Units (mIU) or an amount equal to 1/1000th of an IU per milliliter. A pregnancy test
with a sensitivity of 20 IU/L is more sensitive than one with 50 IU/L.
A blood test administered by your doctor is more sensitive than the early home tests and can be taken between 7 and 12 days after you conceive. However, it is possible that these tests can be done too early and show a false negative result. If you receive a negative result and still do not start your period, another test should be done.
How accurate are home tests?
Home tests are very accurate (around 97%) when used correctly. Some kits come with two tests because mistakes do happen. If you take a test too early, you may get a false negative (when the test says you are not pregnant but you are).
Your body needs time for the hormone to rise to a high enough level to be detected in a test. If the
test comes back negative but you still think you could be pregnant, wait a few days and test again.
False positives (when the test says you’re pregnant but you’re not) are possible but rare. A positive pregnancy test is a pretty good indication that you are pregnant.
Do you want to get pregnant?
Our Ultimate Fertility Resource Guide provides the information you need on fertility, tips on how to get pregnant faster, and how to boost fertility through sometimes simple tweaks to your lifestyle and approach. The guide is easy to read and meant for anybody wanting to increase their ability to conceive. It’s a free download and includes coupon codes for essential products. Even free Nightfood Nighttime Ice Cream.
Want to Know More?
- Things to Know About Ovulation
- Track Your Ovulation
- Are You Trying to Get Pregnant
- Preconception for Women
- Signs of Ovulation
- There are two main types of pregnancy tests: urine and blood tests.
- Take a home urine test after your next missed period — anywhere from 14 to 18 days after conception.
- Blood tests are more sensitive and can tell you if you're pregnant 6 to 14 days after conception.
You have two options when it comes time to see if you have a baby on board.
The most common is an at-home urine pregnancy test, available over the counter, though you can take a urine pregnancy test at a medical clinic. Another option is a blood test performed at a medical clinic.
"Both tests check for a hormone called human chorionic gonadotropin, or hCG," says Crystal Newby, MD, of Kansas City Ob-Gyn. "This hormone is produced after a fertilized egg attaches to the wall of your uterus."
The egg typically attaches 6 days after fertilization, at which point, hCG levels in your blood and urine will increase for the next 6 to 10 weeks. Once hCG levels are high enough, you can expect an accurate reading, but not before then.
When should you take a blood pregnancy test?
Depending on a woman's cycle, a blood test can detect pregnancy between 6 and 14 days after conception.
Blood tests for pregnancy are more sensitive to hCG than home pregnancy tests. They can detect this hormone in low quantities and tell you if you're pregnant sooner than a home test.
While blood tests can provide results sooner than home pregnancy tests, they are usually more expensive and take longer to provide results because the blood must be sent to a lab for analysis.
If the lab is in-house then it will take a few hours. But if the lab is at a different location, it could take several days to learn the results.
When should you take a home pregnancy test?
Most home pregnancy tests advise you to take the test after you miss your next period. If you have a standard 28-day cycle, you'll be most fertile two to three weeks before your period.
So if you get pregnant during that fertility window, you'll need to wait at least 14 to 18 days after conception to take a home pregnancy test.
If you get a negative result and suspect you're pregnant, check the instructions on the box. Home pregnancy tests typically recommend retaking the test 5 to 7 days later, when the hCG levels in your body will be higher.
This type of result is called a "false negative." Sometimes you can receive a false negative result if you take a pregnancy test too soon when your hCG levels are too low for the test to detect them accurately.
Moreover, recent miscarriages, fertility drugs, and rare hCG secreting tumors can interfere with the results of at-home urine tests. If you receive conflicting results after taking a home pregnancy test multiple times, doctors recommend a blood test.
How accurate are pregnancy tests?
Blood pregnancy tests are considered by doctors to be 99% accurate. Quantitative blood tests (also called beta hCG tests) are the most accurate blood tests and can help doctors tell the exact age of the fetus and play a role in detecting any abnormalities.
If you follow directions, home pregnancy tests are an estimated 97% to 99% accurate. If you perform a urine pregnancy test in a lab setting, like at your doctor's office, the accuracy will be closer to 99%. It's important to make sure that you check the expiration date on your home test, as it can affect the accuracy of the results.
After taking either a blood or urine test, it's important to confirm the pregnancy with an early ultrasound.
Insider's takeaway
Home pregnancy tests can provide results faster and be more convenient than a blood test. But you'll probably have to wait longer to receive accurate results.
You can expect accurate results from a blood pregnancy test as soon as 6 to 14 days after conception. Because the test must be analyzed in a lab, it could take up to several days to get the results.
To get the most accurate reading from a home urine test, wait until your missed period. This can come anywhere between 14 to 18 days after conception. If you get a negative result, you can try taking a home test again in 5 to 7 days to see if you have higher amounts of detectable hCG in your body.
Blood tests are considered to be 99% accurate, while home pregnancy tests are around 97% to 99% accurate. Regardless, you should confirm your results by getting an ultrasound.
Denice Rackley is a freelance writer for Insider.
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