If you think you may be pregnant, a simple test using a small sample of urine can usually provide the answer.

How do pregnancy tests work?

A urine pregnancy test looks for human chorionic gonadotropin (hCG), a special hormone that is present only when a woman is pregnant. The body begins to produce hCG the moment a fertilized egg is implanted into the uterus, usually 7 to 10 days after ovulation and fertilization. After that event, the levels of hCG in the blood double every 2 to 3 days, becoming detectable in a urine test approximately two weeks after conception, sometimes earlier.

What are the advantages of using a home pregnancy test?

Home pregnancy tests are inexpensive, easy to use, private, and require only a few minutes of time to obtain results. Furthermore, the test kits are available in most drug or discount stores and do not require a prescription. According to pregnancy kit manufacturers, most at-home pregnancy tests are 97% to 99% accurate when used as instructed. Positive results can be trusted, but falsely negative results can be seen very early in the pregnancy.

Are all home pregnancy testing methods the same?

Most brands are reliable. Although the exact testing method differs from one brand manufacturer to the next, all home pregnancy tests look for the presence of hCG in urine. Some at-home tests require collecting your urine in a cup and dipping a prepared chemical strip into the urine; others require putting a few drops of urine into a special container with an eyedropper; and others involve placing a test strip into your urine stream. The tests also vary in the length of time needed for results to be obtained and how the results are displayed. (For example, some tests sticks change colors or display a symbol to indicate if you are pregnant.) Be sure to follow carefully the instructions provided with your kit. Don't hesitate to call the toll-free number listed in the packaging if you have any questions about how to do the test or read the results.

When should a home pregnancy test be used?

Home pregnancy tests can detect if you are pregnant as early as 7 to 10 days after conception. If your home pregnancy test is negative, test your urine again within a few days to a week. If you think you might be pregnant despite a negative test result, call your doctor or health care provider and schedule an appointment. If you are pregnant, begin taking a multivitamin each day to keep your body strong and prevent birth defects. Prenatal vitamins have the most folic acid in them, but any daily multivitamin, including children’s chewable, will have enough folic acid to prevent the birth defects. Your doctor may change the recommendation as the pregnancy progresses.

What else do I need to know about home pregnancy tests?

Other tips to follow when taking an at-home pregnancy test include:

  • If you wish to use a home pregnancy test kit, be sure to check the expiration date on the package before purchasing. If the kit is past its expiration date, the test results may not be accurate.
  • Use your first morning urine when possible, when hCG levels are most concentrated.
  • Do not drink excessive amounts of fluids before the test to increase the volume of urine. This could dilute the hCG levels.
  • Read the directions included in the test thoroughly before starting the test, and follow every step precisely.
  • Some fertility drugs may interfere with the test results. Most other over-the-counter and prescription drugs, such as birth control pills and antibiotics, should not affect the results of a home pregnancy test. Check the package labeling for additional information.

Always see your doctor if you are unsure about your home pregnancy test results, and always see your doctor if you experience any unusual pain after missing a period—even if your pregnancy test was negative.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 5/23/2014...#4340