Took 3 days antibiotics (Pen Rafa) and had unprotected sex while taking Yaz, (drospirenone and ethinyl estradiol) first week of pills, what are the chances of pregnancy?

Very Very low... Penicillin doesn't change the effectiveness of Yaz (drospirenone and ethinyl estradiol) (or other birth-control pills.) If you are taking the Yaz (drospirenone and ethinyl estradiol) correctly and not missing days, your chances of pregnancy are the same as if you didn't take penicillin: Very very low. (Near zero) Best wishes!

Related Questions

I'm on the Yaz (drospirenone and ethinyl estradiol) bc pill. During week 2 I skipped the pill on mon kept taking it for the rest of the week and had unprotected sex on fri can I get pregna?

Missing pills. If you only missed one pill, you should be ok. Missing just one pill should not decrease the effective of the pill during that cycle. That being said, there is no 100% effective birth control method. The birth control pill is about 98% effective when used correctly. Read more...