Women who use drugs during pregnancy place their unborn children at high risk for being born addicted to drugs. Such children may also be born with birth defects and may experience learning and behavioral problems. Methadone, a synthetic narcotic, is commonly prescribed to treat opioid addiction. It may not be an optimal solution for opioid-dependent pregnant women, however, because a large percentage of children born to women taking methadone experience severe drug withdrawal symptoms at birth that often require medical treatment. Common opioid withdrawal symptoms, described as neonatal abstinence syndrome (NAS) in babies, include tremors, irritability, sleep problems, seizures, dehydration, and fever. Buprenorphine is a medication that has been approved to treat opioid dependence in individuals who are not pregnant but has not been approved for pregnant individuals. Past research has shown that use of buprenorphine in pregnant women results in improved birth outcomes over methadone. The purpose of this study is to evaluate the effectiveness of buprenorphine versus methadone at reducing opioid withdrawal symptoms in babies born to opioid-dependent women.