The effect of methadone dose regimen on neonatal abstinence syndrome

To evaluate the effects of a multiple daily dose methadone regimen in pregnancy on neonatal outcomes.

Although methadone maintenance has been the standard for the treatment of opioid dependence in pregnancy, there is no consensus on proper dosing. Single daily dosing is the most common strategy. Because of accelerated metabolism of methadone in pregnancy, this regimen may expose mother and fetus to daily episodes of withdrawal and possibly contribute to more severe Neonatal Abstinence Syndrome (NAS). This study reports on a protocol that increased both methadone dose and dose frequency in response to maternal reports of withdrawal.

Treatment of NAS was needed in 29% of neonates, compared to a published rate of 60% to 80%. The mean methadone dose was 152 mg at delivery, divided into 2 to 6 doses per day. Ninety-two percent of mothers were free of illicit drug use at delivery. There was no relationship between methadone dose and treatment of NAS. Female babies had a treatment rate of 16% versus 38% for male babies. Beyond abstinence symptoms, cohort outcomes in terms of gestational age, birth weight, prematurity, Caesarian sections, and breastfeeding equaled or approximated US population norms.

The protocol was associated with low rates of treatment of NAS and high rates of maternal recovery. High rates of treatment for NAS reported in methadone-exposed neonates might relate in part to iatrogenic factors and be reduced through the use of divided daily doses and protocols that minimize maternal withdrawal.