Heather Corinna replies:
My girlfriend and I have been having sex for awhile but recently she had her period. And we both couldn't wait so we had sex during it without a condom. Could she still get pregnant even during her period?
For most women, pregnancy is substantially less likely from intercourse that happens during menses than from intercourse at other times. However, since sperm can live in the vagina for several days, and some women ovulate early in their cycles, for some women, unprotected sex during menses -- especially at the very end of it -- can be just as much of a pregnancy risk as during other times of the fertility cycle.
And in the future, I strongly urge you not to gamble with pregnancy and STI risks, especially considering how easy it is to be more responsible about sex. It's very easy to keep condoms handy at all times and always use them, and it's also easy to just stick to outercourse and other activities -- things like mutual masturbation, dry sex, even manual sex -- which don't present these risks if you want to be sexually active when you don't have latex barriers around.