Oxytocin is a peptide hormone or neuropeptide. Oxytocin is released from the posterior pituitary gland located in the brain. It regulates social interaction and sexual reproduction, playing a role in behaviors from maternal-infant bonding and milk release to empathy, generosity, and orgasm. The two main actions of oxytocin in the body are contraction of the womb (uterus) during childbirth and lactation. Oxytocin stimulates the uterine muscles to contract and also increases production of prostaglandins, which increase the contractions further. That is why, oxytocin is called birth hormones.