In the first few days after delivery, your uterus contracts. These uterine contractions, which resemble cramps, can be more intense during breastfeeding. "This is nature's way of healing the body," says Leigh Anne O'Connor, New York-based certified lactation consultant. "This reduces maternal bleeding and contracts the uterus." Although it is a common occurrence post delivery, not all women experience uterine contractions during breastfeeding, O'Connor notes.