Possible Reasons for a Missed Period While on Birth Control

Question
Dear Dr. Rappaport:

I was supposed to start my period about 7 days ago.  I am currently on Ortho-tricyclin and have been for 5 years.  I know some people get lucky and either stop getting their period completely, or have a very light one.  I, on the other hand, have been very regular and my period is typically at least 5-7 days.  In other words, it is very unlikely that I just happen to miss a period this time. I took a pregnancy test about 4 days after I missed my period and it came up negative.  About 2 1/2 weeks ago I experienced some moderate bleeding that was very mucousy in consistency but it definitely was too early and too light to be my period.  At this point I feel like I am on my period (cramping, bloaty, etc.) but there is no bleeding at all!

My question is, is it possible that I am pregnant and the test is wrong or too early?

Could the cramps be a sign of early ectopic pregnancy?
and...

What might the between period bleeding be? Could it be related to my missed period?

Answer
If you have not missed any pills, it is highly unlikely that you have become pregnant (either ectopic or intrauterine)especially since you had a negative pregnancy test. Sometimes, when on the pill, you can miss a period once in awhile. I would just keep a careful record of your bleeding from now on and see if you get your normal period next month. Continue with the pills. (Even if you are pregnant, there is no harm in continuing the pills until the beginning of the second trimester). If you don't get your period next month, contact your doctor.