Why can’t women get pregnant without the menstrual cycle? (2016)
 TL;DR => Menstruation in human females is a monthly self-cleansing (although wasteful) FLUSH to get rid of all those "unworthy" scum who didn't make it as viable fetuses. Because being considered "worthy" by mother grants you (the fetus) root-level, administrator access to her body (Yes, we human fetuses are that aggressive and we don't know why!). So be warned that there is a tough screening process going on before you get accepted and gain root-level permanent access!!! Otherwise you will end up in nasty menstrual blood!