This study compared five groups of participants: those receiving either three-day methadone-assisted withdrawal (MAW) alone (n = 67), three-day MAW followed by methadone maintenance (MM) (n = 8), seven-day MAW alone (n = 28), seven-day MAW followed by MM (n = 20), or a continuous MM sample (n = 52) enrolled between 1995-2001 in an urban drug treatment center. On average, patients in the three MM groups remained in treatment longer, attended more obstetrical visits, and more often delivered at the program hospital than patients in the two MAW alone groups. Given the poor maternal MAW outcomes, methadone maintenance should be considered as the primary treatment approach for opioid-dependent pregnant women.