Background and aims
Although methadone maintenance therapy is the standard of care for opioid‐dependent pregnant women, there exists controversy over the benefits and side effects of treatment to the neonate. Our aim was to document predictors of neonatal outcomes within an opioid‐using population, with particular reference to methadone treatment in the context of continued heroin use.

Methods
Analysis was performed on a cohort of 183 opioid‐using pregnant women seen by the Sydney South West Area Health Service between 2004 and 2007 and between 2009 and 2011. Neonatal outcomes were analysed according to maternal opioid use: methadone only, methadone and heroin, or heroin only. Logistic regression was used to examine independent predictors of neonatal outcomes.

Results
No difference in the frequency of low birth weight neonates or the rate of prematurity was found between the methadone‐only, methadone‐and‐heroin and heroin‐only groups (P = 0.30; P = 0.42). Methadone treatment was not found to increase the treatment requirement for neonatal abstinence syndrome compared with those using heroin only (P = 0.91). Women using methadone only were more likely to retain custody of their child at hospital discharge than women using methadone and heroin and heroin only (80.4, 59.0, 40.0%; P < 0.001). Conclusions Methadone treatment was beneficial in predicting the discharge custody status of the neonate. Engagement with antenatal care was found to reduce the likelihood of preterm birth and to be independently associated with the neonate being discharged in the care of the mother. Women who continue to use heroin should not be denied methadone treatment for fear of worse neonatal outcomes.