Is neonatal abstinence syndrome related to the amount of opiate used?

Objective: To determine if a relationship exists between the dose of heroin and/or substitute medication used in pregnancy and neonatal abstinence syndrome (NAS). Data Sources: Ovid online was used to search the following: EMBASE, Ovid MEDLINE, CINHAL, PscyINFO, Cochrane Database of Systematic Reviews. Study Selection: English language journal articles reporting original research undertaken and published between 1995 and 2009 that examined relationships between NAS and opiate use in pregnancy and with patterns of substance abuse that reflect those of the United Kingdom and other high-resource settings. Data Extraction: The studies were reviewed independently by two authors using predefined quality criteria. Data Synthesis: This was a narrative review; key messages from included studies were discussed in the context of the diversity and commonality of findings in relation to NAS. Conclusions: No correlation between the amount of fetal opioid exposure and expression of NAS was reported in eight of the 10 studies. This observation was consistent across international boundaries, and studies that included both methadone and buprenorphine.