Can Ondansetron Prevent Neonatal Abstinence Syndrome (NAS) in Babies Born to Narcotic-dependent Women

The Investigators hope to learn if they can prevent or lessen the symptoms of neonatal abstinence syndrome (NAS) in babies born to narcotic-dependent mothers by using the drug ondansetron in the mothers prior to delivery and their babies after delivery. The study is a randomized, double-blind, placebo-controlled study with one half the mother-baby pairs to receive ondansetron and the other half of the mother-baby pairs to receive placebo. The pregnant narcotic-dependent mothers will receive an intravenous dose of study medication prior to delivery; the neonates, after their birth, will receive the same study medication the mother received every 24 hours for up to 5 days. The Investigators will follow up with the mother-baby pairs for 10 days after study drug has stopped and one last follow up, about 30 days after stopping study drug, to learn if the baby had any symptoms of NAS in that time period.