So my girlfriend has been on the pill for like 4 years. She is now on week 2 of her birth control. She just finished a whole bottle of antibiotics 3 days prior, for a sinus infection. The bottle nor doctor said a back up method of birth control was necessary. We had unprotected sex last night, but we keep researching that we were supposed to wait a week to a month before relying on the pill again. Any input? Thanks.

You read correctly. Some antibiotics render the pill completely ineffective.

First even without other medication, the Pill is not 100 percent effective, and 1000's of women get pregnant each year just using the pill.

The other medication can make it less effective.

So yes there is concern because thre can be pregnancy

First even without other medication, the Pill is not 100 percent effective, and 1000's of women get pregnant each year just using the pill.

I understand that, nothing is 100%, except for abstaining.

So yes there is concern because thre can be pregnancy

I understand that, nothing is 100%, except to abstain altogether. All I know is when she got a bad flu virus they put her on antibiotics. & the bottle specifically read "use backup method of birth control", plus the dr told her a backup had to be used. But this time her bottle nor Dr. stated a backup had to be used. I wonder why.

You read correctly. Some antibiotics render the pill completely ineffective.

So how do you know which one's render effectiveness & which ones do not? The first antibiotic she was on like 1 year ago read that a backup was necessary, along with the doctors confirmation. However this time, nothing. Lol