I am on birthcntrl and took antibiotics. i had sex everyday while on keflex. now i'm 3 days late, with very light pink bleeding. digital test said no?

Antibiotics vs BCP: Study after study shows that only Rifampin affects the effectiveness of birth control pills. So as long as you take your bcp at same time every day, your chances of getting pregnant are slim. Check out http://www.Mayoclinic.Com/health/birth-control-pill/wo00098/nsectiongroup=2 & http://www.Plannedparenthood.Org/health-topics/ask-dr-cullins/dr-cullins-birth-control-5444.Htm.