Robin Elise Weiss has an interesting and informative comparison of the effects of oxytocin and pitocin during childbirth.
Oxytocin is the hormone and neurochemical produced in the body by the pituitary gland. It's released in waves to speed the baby through the birth canal. Pitocin is an artificial form, administered as a steady drip during medicalized labor or to induce labor.
A key point Weiss makes (although I don't think this has actually been proven scientifically yet):
Pitocin can interfere with bonding. When the body releases oxytocin, also known as the love hormone, it promotes bonding with the baby after birth. Pitocin interferes with the internal release of oxytocin, which can disturb the bonding process.
Weiss is a childbirth and postpartum educator, certified doula, doula trainer, lactation counselor -- and mother of seven!