It wont effect the effectiveness of her BC but I personally prefer not to take them for 2 reasons. First, BC pills increase the level of estrogen which seems rather counterproductive when taking Anabolic Androgenic Steroids (AAS) to get the full benefit of the AAS. Second, I tend to miss my period the first month on anavar and then have spotting at various times. It just puts my mind at ease when I miss my period knowing that I havent had unprotected sex even though I know Im missing my period because of the anavar and not any other reason. Despite the fact that it will still be effective, I would use another method of birth control while taking Anabolic Androgenic Steroids (AAS) although many women still do take the pill. Chelsea