Expert: Brigid Kowalczyk - 3/20/2006

Question
Hello Dr.,

I am also not a huge fan of birth control pills but after months of using the natural method, my husband and I decided to try a low-hormone pill (microgestin) to be "worry free"  until we start trying for a baby later this fall.

My question is this:

I started taking Microgestin at the beginning of January, and am now on my 3rd cycle using it.  Typically, I have been getting my period on either day 27 or 28. (when not on BC, my normal cycle is usually around 25 days though).

I was an antibiotics for the past 2 weeks (a cousin to penacillon, but can't remember the specific name - started with a C).

I started to bleed last night - which was only day 21 (an entire week early).  I also had really bad cramps most of the night, and still today.  However, today I am not bleeding much - just a few spots.

I am wondering:

a) Did the antibiotics effect my cycle, in combination with the pill?

b) If my period truly is here, what do I do about the remaining 6 pills I am supposed to take (normally not during a period)?  And next week, do I continue to take the non-hormone pills?  Will it just prolong my period another week?

and c) Is there any I could be pregnant?  I read through my research today that antibiotics can weaken the effectiveness of the hormones in the pill.  But I would not be bleeding if I were pregnant, would I?

I appreciate your help.

Sincerely,
Jennifer Thomas

Answer
As you can see, the pill does not come "worry free".  At least with the natural approach, you don't have any outside influences to confuse what your body is telling you.  

Antibiotics do interfere and reduce the effectiveness of the pill, especially the mini pill, which doesn't have as much hormone in it to begin with.  

I don't know if you had a real period or just break through bleeding.  You should get a pregnancy test because you shouldn't take the pill if you are pregnant, it isn't any better for the baby than it is for you.

Sometime women bleed even if they are pregnant, not usually but it isn't unheard of.