No period / negative HPT

Hello,
I am on Sprintec birth control pills but may have missed one or two and followed the next day with two pills. I also take Topamax and recently learned this interacts with birth control. My period is extremely regular, always coming during the last 4 days of the "white" pills, with blood & uterine lining as normal. This month I did not have my period -- it is now almost a week late. I had the tiniest drop of brown discharge and some clear/jelly like uterine lining (?) discharge at one point, but that was it...nothing like my usual period. I took a couple HPTs and they came back negative. however, this is unusual for my body. I've never not had any blood. If I was pregnant, it could only be 3 weeks max...Should I be concerned, or just assume the 99% accuracy advertised on the pregnancy test is correct and I am not pregnant?  Thanks!

[Elaine Brown, MD]

Hi!
Home pregnancy tests are very good if done correctly.  It is important to use the first morning urine to test with.  It is also important to be far enough along to test.  If you were my patient, I would reassure you that you are probably not pregnant, and the missed period is likely due to the missed pills.  BUT, I would have you continue to test weekly until the next period comes or the test is positive.
I advise my patients not to stop their pills unless their test is positive!
Good luck!
Dr B