Final answer:
Oxytocin is the hormone added to the intravenous solution after delivery of the placenta to stimulate uterine contractions and reduce the risk of postpartum hemorrhage.
Step-by-step explanation:
The medication that is often added to the intravenous solution after the delivery of the placenta is oxytocin. Oxytocin is a hormone responsible for stimulating uterine contractions during labor and to help reduce postpartum hemorrhage by contracting the uterine muscles after the placenta is delivered, thus preventing excessive bleeding. Given the importance of oxytocin in the labor process, as it promotes the contractions that help in the expulsion of the fetus and placenta, it is routinely administered postpartum to ensure the uterus continues to contract and to minimize the risk of hemorrhage. Following delivery, the increased sensitivity of the myometrium to oxytocin due to the higher expression of receptors aids in efficient uterine contraction and involution.