Missing a period can be a sign of pregnancy, but a delayed or missed period can be the result of other hormonal changes in the body, including high levels of physical or emotional stress. Many women will have delayed or skipped periods at least once in their lifetime. Pregnancy testing helps identify if a missed period is due to a pregnancy or not.
Method
Pregnancy tests, WomensHealth.gov explains, work by detecting a hormone called hCG, also known as human chorionic gonadotropin, which is produced by the body during pregnancy. This hormone is made once the fertilized egg has implanted in the uterus and rapidly accumulates in the body of pregnant women.
Types
Human chorionic gonadotropin can be found in both the blood and the urine of a pregnant woman. Consequently, according to Lab Tests Online, a pregnancy test can be performed on either the blood or the urine. Blood pregnancy testing is generally only available from your doctor, whereas urine-based pregnancy tests can be performed using a home pregnancy testing kit.
Home Pregnancy Tests
Home pregnancy test kits can be purchased over-the-counter at many drug stores. These tests generally have similar instructions, WomensHealth.gov explains. All involve exposing the testing stick to urine, either by urinating directly on the stick or by collecting urine in a cup and dipping the stick in the urine. After a period of time, which varies from brand to brand, the results of the test will be displayed in the "results window." A positive pregnancy test may display a plus symbol or a line, though digital tests now display the word "pregnant."
Accuracy
Most pregnancy tests claim to be 99 percent accurate the day after a woman's first missed period, but a number of factors can interfere with their accuracy. Tests must be used properly for optimal accuracy, so women should be sure to carefully follow the test's instructions. In addition, it can take several days for hCG to build up to detectable levels in a pregnant woman's blood, so home pregnancy tests taken in the first week after implantation may give a false-negative result.
Result Interpretation
Because it is possible to get incorrect results from a pregnancy test, additional steps are necessary after any home pregnancy test result, the Mayo Clinic explains. Women with a positive result should have their doctor perform a more sensitive pregnancy test to confirm that they are pregnant. Women with a negative result should repeat the home pregnancy test if their period has not arrived within a week after the first negative result.
