Yes, it is safe to have sex during menstruation. Menstruation is little different to any other point in the menstrual cycle, although the cervix may sit lower in the. If a girl has sex with a guy during her period, she can still get pregnant. And guys and girls also can get sexually transmitted diseases (STDs) during this time — in fact, having sex when a girl has her period can make it even easier to spread some STDs. So always use a condom every time you have sex.