Negative Pregnancy Test
Definition - What does Negative Pregnancy Test mean?
Negative pregnancy tests can occur when no pregnancy is present, or when pregnancy tests are taken very early in pregnancy. Rarely, other factors such as a low-hormone pregnancy or dilute urine can also cause a false negative on a pregnancy test.
FertilitySmarts explains Negative Pregnancy Test
Pregnancy tests work by measuring human chorionic gonadotropin, or hCG. This hormone is produced by the placenta during pregnancy, and is not normally found in detectable levels in people who are not pregnant.
It is possible for a pregnancy test to fail to find hCG, even if pregnancy is present. Reasons include:
- The test is taken too early in pregnancy. This is by far the most common reason for false negative pregnancy tests. Because the placenta starts out with a microscopic ball of cells, hCG levels may not become detectable levels until up to three weeks after conception.
- Urine is too dilute. Pregnancy tests are most accurate when taken first thing in the morning, when urine is highly concentrated. If the test is taken after drinking a lot of water, the water may dilute the hCG to undetectable levels.
- Low-hormone pregnancy. hCG levels are not the same in every pregnancy, and, rarely, a pregnancy may occur which does not become detectable in the normal time frame.
Cases where a period is missed but pregnancy tests are negative may warrant examination by a doctor, as this could signal complications such as an ectopic or distressed pregnancy.
There are also non-pregnancy causes of missed periods, such as hormone imbalance.