I've never had a biopsy affect my cycle. I don't know if anyone else has, but it seems highly unlikely it would.
If you have reason to believe you are pregnant than please get the pregnancy test. I know the doctor won't do the LEEP if you are pregnant, but wouldn't it be worse not knowing?
I was pregnant when I was told I had CIN III. I had to wait from Nov. 05 until after I delivered in Jun. 06 to even have the biopsies done to confirm the CIN III pap results. I was scheduled for my LEEP in Sept. 06, but it had to be pushed back when my bloodwork done a week before hand showed I was pregnant again. Unfortunately I miscarried the same week (next day to be exact) and I was able to have the LEEP done in Oct. 06. I haven't had any "relapses" since.
So yes, a pregnancy may not be "ideal" but it's something you can deal with. Please keep us posted.