Can I Get A False Positive or False Negative Pregnancy Test?

6. Question: Can I receive a false positive pregnancy test? Or a false negative?

Answer: A false positive is a rather rare occurrence indeed. The two most common causes of, or explanations for, a false positive are 1) Use of hCG-containing fertility drugs (clomid is not one of them) and 2) improper use of test or failure to observe guidelines on test interpretation. With regard to the latter explanation, a false positive associated with improper use is typically caused by an attempt to interpret a test result after the given “reaction time” of a test. With most tests, you should not read a result after the five or ten minute time interval specified by the manufacturer. Hardly anything (besides fertility drugs) can interfere with a preg test result, so a true false positive is not a common occurrence.As for a false negative, these may be more common due to the issues discussed in Questions 4 and 5 about hCG production, rates of hCG increase, and testing tips. If you do elect to test early, we always advise to take follow-up tests to account for various variables that may postpone or slightly delay a first positive result. Such variables include date of implantation, concentration of hCG in a given urine sample, specific rate of hCG increase (depends, in some cases, on where in the womb the fetus implants). Again, please view our Buyer’s Guide to ensure maximum accuracy!

Finally, a chemical pregnancy is a not entirely uncommon phenomenon generally associated with actively trying-to-conceive women. That’s because TTC couples will be testing, on average, sooner. A chemical pregnancy is when a fertilized embryo implants briefly in the womb (long enough to produce the hormone hCG) but the pregnancy does not “take”, and is followed by normal menstruation. Hence, in such a particular situation, you can get a positive result and, several days later, find yourself quite surprised and disappointed with a series of negative results. A chemical pregnancy is not at all rare, and therefore it is one of the emotional hazards of early-detection tests.

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