Can I use a menstrual cup if I have had a child?

Yes. The cup that I am most familiar with is the diva cup. It comes in two sizes - model 1 is for women who are under 30 and who have never delivered a baby, either vaginally or by cesarean section. Model 2 is for women who are over 30 or who have delivered a baby. Diva cup has a great website with answers to many menstrual cup questions: http://www.Divacup.Com/.