Why do my bowel movements change when I get my period?

1) I've suffered weird digestive things when I have my period. The way I have heard it explained in my MCAT class is that the same hormone that causes the smooth muscle of the uterus to contract unfortunately works on all of our digestive organs as well, particularly the large intestine. So that's how I've come to grips with the apparent confusion of the digestive processes during my period.

2) Does a person's menstrual cycle regulate her bowels in any way? I have had some problems. The week before I get my period, I have loose bowels and the week afterwards I am quite constipated. Is this normal? Is there anything I can do?


Is menstrual synchrony fact or fiction?

Okay, so my mother does not believe, as I do, that when a group of women live closely together (i.e., in a dorm setting) that their menstrual cycles become roughly similar, due to the release of pheromones. I'm pretty sure that I heard this somewhere, but I can't find anything to back it up. I swear I'm not making it up, but my mom doesn't believe me.

Thanks for your help.