If you are trying to become pregnant or suspect you might be, finding out for certain is probably at the forefront of your mind. You might be tempted to run out and take a pregnancy test days after you think you might have conceived. While many women can get accurate test results before they even miss a period, testing too early can lead to inaccurate results and frustration.

When to Take a Pregnancy Test

As a general rule, you can expect accurate results on a pregnancy test on the first day of your missed period, or 14 days past ovulation. If you are especially anxious to confirm or rule out pregnancy, you can begin testing as early as seven days past ovulation. By 10 days past ovulation, your odds of getting accurate results from a pregnancy test improve drastically. The reason for this is straightforward science and is based on how pregnancy tests work.

What the Pregnancy Test Detects

When you are waiting for that all-important positive line to appear, what you are actually waiting for is the pregnancy hormone to react with antibodies that have been applied to the pregnancy test strip. The pregnancy hormone is called human chorionic gonadotropin (hCG). When the hCG comes into contact with the antibodies, a special dye is activated. This dye forms the positive line on the strip.

How hCG is Produced

Conception occurs when a woman’s egg is fertilized. It may be several days, however, before that fertilized egg implants into the uterus. When it finally does implant, cells from the placenta begin to secrete hCG. The hCG helps to support the growing fetus by stimulating the production of estrogen and progesterone. As the pregnancy progresses, a woman’s hCG levels increase rapidly and will eventually begin to double every 48 to 72 hours. For many women, hCG levels are detectable by 10 to 11 days after ovulation.

Best Pregnancy Tests

Most early pregnancy tests on the market can detect hCG levels of 25 mIU or less. When shopping for a home pregnancy test, read the box to find out the detectable levels of that brand. Obviously, the lower the number, the earlier you can test. Unfortunately, many digital tests cannot detect hCG levels lower than 50 to 100 mIU.

Reading Your Pregnancy Test Results

Especially when testing early, the results of a home pregnancy test can be confusing. Remember that the colored line–no matter how faint–that appears in the positive result window within 10 minutes of testing is a reliable result. Also, remember that the hCG in your body may not reach detectable levels until 14 days past ovulation. If you get a negative test result, wait two days and test again. If you continue to get negative results and your period does not begin, see your doctor.

How to Read a Pregnancy Test: