The results of a pregnancy test can make a dramatic difference in a woman's life. When a woman takes a pregnancy test and receives a negative result, she would like to trust that result. However, negative pregnancy results cannot always be trusted. Learning the specifics about negative pregnancy test results will allow her to know if she needs to retest or can safely trust the result and assume she is not pregnant.
Types
Many different pregnancy tests are available, and each displays negative results in a different matter. Quantitative blood tests measure the exact amount of the pregnancy hormone human chorionic gonadotropin (hCG) in the bloodstream, which makes it the most accurate type of pregnancy test. Qualitative blood tests only measure whether or not the HcG hormone is present and are about as accurate as urine pregnancy tests, explains the U.S. Department of Health and Human Services. Since a doctor or clinician typically administers blood pregnancy tests and interprets the results, the woman will usually have a negative result given to her verbally. On the other hand, a woman will need to read and interpret the results of a home pregnancy test herself. Traditional home pregnancy tests display only one control line for a negative result and display two lines or a plus sign for a positive result. Digital home pregnancy tests typically display words like "Not Pregnant" for a negative result, and "Pregnant" for a positive result.
Misconceptions
Due to the many advertisements for home pregnancy tests that brag about the ability to test several days before a woman even misses her period, many women mistakenly believe testing before their period is due is not an issue. However, the fertilized egg may not implant and release the hCG hormone until after a period is due, explains that U.S. Department of Health and Human Services, so testing before this time puts a woman at risk of receiving a false negative result. The Mayo Clinic recommends all women wait until after a missed period before taking a pregnancy test and explains that waiting as long as a week after a missed period to test will provide the most accurate results.
Considerations
Drinking too much water right before testing can dilute the amount of HcG in the urine. This may contribute to a negative result on a urine-based pregnancy test when a woman is actually pregnant, explains the Mayo Clinic. For this reason, it is always best to avoid drinking too many fluids for a few hours before taking the pregnancy test. It is also a good idea to use the first urine of the morning if possible, as urine is less diluted at this time than at other times of the day. Performing home pregnancy tests incorrectly also may cause a false-negative result. It is always best to follow the directions of the pregnancy test perfectly to be sure the results are as accurate as possible.
Evaporation Lines
Sometimes a home pregnancy result that looks positive can actually be negative. This occurs when a home pregnancy test gets something called "evaporation lines." When the urine evaporates from the testing strip, sometimes a shadow of a line is left. Many women mistakenly take these evaporation lines as a positive result, when in fact they are not pregnant. To avoid this happening, always read the results of a home pregnancy test within the recommended time frame, which typically about 10 minutes after taking the test. Lines that appear after this time frame may be evaporation lines and should be disregarded.
Warning
If a woman gets a negative result on a home pregnancy test but does not receive her period within a week after testing, she should consider retest or visit her doctor to confirm she is not pregnancy. A doctor may use a quantitative blood test or do a pelvic exam or ultrasound to determine whether she is pregnant
