Polydrug use among pregnant methadone users

Methadone maintenance treatment (MMT) is used to manage opioid dependence. However, the common practice of polydrug use poses a serious concern with women co‐abusing substances during pregnancy. The objective of this study was to assess polydrug use in pregnant methadone users by meconium result analysis. Meconium samples were collected from the Motherisk Laboratory for testing as per requests by children's aid societies and hospitals. Over 22 months, samples were tested for substances of abuse through immunoassay (ELISA) or GC‐MS analysis. All methadone positive samples were used to assess frequency of polydrug use in a high‐risk pregnant population with methadone negative samples serving as controls. Of the tested samples, 117 were positive and 88 were negative for methadone. Opioids were the most prevalent drug class detected for both groups (44.4 and 50% respectively). No statistical difference was found for the prevalence of any individual or class of drug, with the exception of codeine (p=0.042), nor for the average minimum number of drugs detected (1.33 (SD=1.05) and 1.55 (SD=1.30) respectively). With opioids being the most prevalent drug class, this could suggest that opioid dependence is not effectively managed in a substantial fraction of individuals on MMT. With a high rate of polydrug use, it is pertinent to study the effects this can have on the fetus in future research.