Assertion: period's pain | /r/CreatedBy | uterine contractions
Facets:
Source sentences:
text: The pain is caused by uterine contractions that happen just before or during the onset of your period.
text: Pain from menstrual cramps is caused by uterine contractions, triggered by prostaglandins, hormone-like substances that are produced by the uterine lining cells and circulate in your bloodstream.