I had a quick question. My girlfriend and I had maybe 5 seconds of penetration, no cum, around the end of january. She is a Sunday starter on yaz, and had only been on it about 5 days. Well she went ahead and had her period in February, just wondering what the chances could be of pregnancy? The only thing she's feeling lately have been tender breasts, but she's pretty sure that's a side effect of the yaz.