Is Menstruation an Abomination?

Leviticus 18 appears to lay out laws for all peoples, not just those under the Mosaic code. However, one item among the list of abominations in that chapter is no longer widely condemned today, and the question is why not? Are we sinfully ignoring the bible, in which case we need to be brought to repentence, or has something changed about a woman on her period which gives her a different spiritual status now than such a woman would have had during the times of Israel?