This study will examine differences in fetal neurobehavior at peak (2 hours after oral dose) vs. trough (2 hours before oral dose) plasma methadone levels. Anecdotal clinical observations suggest that fetal activity is increased at trough methadone levels and decreased at peak methadone levels, yet the investigators do not understand how in utero methadone exposure affects fetal neurobehavioral state development.
The purpose of this study is to examine differences in fetal neurobehavior at peak (2 hours after oral dose) vs. trough (2 hours before oral dose) maternal plasma methadone levels.