can sperm cause menstrual flow to increase?
in length of time and/or intensity?
sorry folks you're too slow and g**gle rulz!
sperm contains prostaglandin, a hormone that regulates the human reproductive process in many ways. One of these ways is to cause uterine contractions, which cause more menstrual blood to be squeezed out, thereby making the time of flow shorter. For up to a day or so I suppose it would make it heavier though.