Growth and developmental outcome of infants with in-utero exposure to methadone vs buprenorphine

Objective: To compare early growth and developmental outcome of infants with in-utero exposure to low-dose methadone (<100 mg per day), high-dose methadone (⩾100 mg per day) and buprenorphine. Study Design: A retrospective review of infants with in-utero methadone and buprenorphine exposure who were evaluated at the Southcoast Developmental Pediatric clinic in New Bedford, MA, USA was completed. Growth data and developmental testing results during infancy were compared among the groups. Result: Infants in the high-dose methadone group had lower head circumference z scores and a lower mean score on the Alberta Infant Motor Scale (AIMS). Regression results confirmed an association between methadone dose and head circumference z score and AIMS score. Conclusion: Exposure to maternal methadone dose in excess of 100 mg is associated with a reduction in infant head circumference when compared with buprenorphine or lower dose methadone, and may have a negative impact on motor skill development during early infancy.