Online pregnancy tests work by calculating a mathematical probability result based on information submitted online, such as menstrual cycle details, intercourse dates and observed physical changes, as described by the Crossroads Pregnancy Resource Center, a nonprofit organization serving women in Louisiana that also offers free online testing. Two other websites that offer free online pregnancy tests are NegativePregnancyTest and EarlyPregancyTester.
Online pregnancy tests should not be considered as medical advice and should also not replace a home pregnancy testing procedure that accurately detects the presence of the pregnancy hormone in urine. A negative online test result does not completely rule out the possibility of an actual pregnancy, as advised on the Negative Pregnancy Test website.
The Early Pregnancy Test website describes its free online test system as a patented software technology that analyzes more than 80 relevant physical details to calculate a negative or positive result. The website also claims that more than 10,000 women take the test each day.
In addition to submitting menstrual cycle and intercourse details, the online test offered by Crossroads Pregnancy Resource Center involves checking off boxes that indicate specific physical symptoms of pregnancy such as frequent urination, abdominal pain, bloating, a change in appetite, fatigue, vomiting or nausea. The website describes the online test result it provides as a probability calculation that indicates a likelihood rather than a guarantee of a pregnancy.