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"Could medication cause false negative pregnancy results?"


I am taking levothyroxine for hypothyrodism and also taking prenatal vitamins as well as metformin to regulate my periods and ovulation to help conceive. I'm also on several other vitamin supplements prescribed by my Dr due to deficiencies as well as a daily allergy med(zyrtec) I am only 3 days late but have been extremely nauseous and taken 3 tests that show negative could any of those meds cause a negative result? I'm also on xanax which I need to stop as soon as I got pregnant due to anxiety...


There are no medications to my knowledge that can cause a false negative pregnancy test. If used properly, the pregnancy tests that can be purchased over the counter at the grocery store or at the pharmacy have a very high sensitivity. This means that they are able to pick up pregnancy when its present very easily and accurately.

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Since you are on Metformin to regulate your periods, I imagine that you have or might have polycystic ovarian syndrome. If this is the case, then having periods that are a little irregular is not that surprising. Because you are on Xanax, I agree that you should check to see if you are pregnant with any sign that you are late so that you can stop that medication, if your doctor allows. I suggest that you schedule an appointment with your OB/GYN. The two of you should discuss your medication list and decide what you need to continue at this time as you prepare to try and get become pregnant. Perhaps you can try and wean off the Xanax before you get pregnant. Your doctors should also make sure that your thyroid hormone levels are not too high or too low as this could make getting pregnant challenging. Good luck.

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