This is a very muddy and full of contradictions for many couples and that's not counting can still be taboo. The question is being practiced or sex during menstruation?. Generally it is practiced and always depending on the couple.
There are women who, during the period do not feel like having sex at all. Hormones generally responsible for decreased libido, others though in those days feel more sexy and above all more excited and female. As the woman's body is very complex, we can not say that they are incompatible.
The only consideration to be taken, if you're of women in those days you are to make the best sex sessions with your partner, is whether he would like. Not all men or all women accept sexual intercourse during menstruation, for various reasons, but the most common are unscrupulous or just do not excite at all.
But if the couple agrees, there is no problem in it. And all is consider to be even more extreme hygiene. Since women in these days tends to be more vulnerable to vaginal infections. Always use condoms.
Therefore, it is dangerous not just all depends on the couple and the prejudices they may have, both women and men leave the taboo in the inkwell.