Late Period & Negative Pregnancy Tests: What Could It Be?

Question
Hi,

I'm on oral contraceptives (about 10+ years) and have a regular 28/29 day cycle.  My last period was December 15, 2006, so I'm a few days late now on January 16th.  I've taken 3 home urine pregnancy tests that have been negative (3 different days).  Is it too soon for the urine tests to work?
I'm planning on calling my doctor and having a serum test if don't start my period by the end of this week.
I'm worried that I'm pregnant, or something else is going on. I'm a relatively healthy 31 year old woman (a little overweight, but BMI < 30).
Any advice would be appreciated.

Thank you.

Answer
Dear Susan,

It could be just a fluctuation in your hormones - for whatever reason. It could be as simple as a change in your diet and stress over the holidays.

If you have taken your BCPs without missing a day (or having a big delay in taking one or more) and have not been sick with vomiting during the last cycle, then I would expect that the birth control success you have had over the past ten years would continue.

Home pregnancy tests do claim to be able to give a positive result on the first day of a missed period, but I typically recommend waiting until after the full week of a missed period. Variances in ovulation days may create a situation where a test will come back negative during a period week, only to come back positive the next week.

If you don't get your period at all, then go ahead and get the serum beta hCG done at the beginning of the following week so your mind is at ease before starting another month of pills. If it is negative, I'd go ahead and stay on the BCP and see what happens next cycle. The general recommendation is that if you miss three consecutive periods you should see your doctor to determine a cause.

I hope this information has helped you and answered your questions. I wish you well.

Brenda