Am I safe while on birth control pills?

Dear Ask The Doctor: I am taking birth control pills and and i wanted to know what are the risks of me getting pregnant if my boyfriend were to ejaculate inside my vagina without a condom. Also, are those the same risks when Im on my period and taking the pills, because I understand the pills are not composed the same for that week.

Dear Sonia: When taken properly, birth control pills are 98 to 99 percent effective, in preventing pregnancy with no additional precautions. The risks do not change while on period, since ovulation is not expected to occur (pills act to suppress ovulation and thereby prevent pregnancy to occur) with the use of birth control pills.