A new study has found that women who began methadone maintenance therapy (MMT) during later stages of pregnancy did not have increased risks of many perinatal adverse health outcomes compared to pregnant women who initiated the treatment for opioid use disorder earlier. However, it also found that perinatal adverse events were generally higher among women treated with MMT compared with the general population, and that later initiation of methadone was associated with a risk of children being discharged from hospital to social services.

Methadone prevents intoxication and withdrawal with continuous daily dosing, which helps create a healthier environment in which a fetus can grow. Studies have shown that babies of mothers receiving MMT tend to have fewer complications than babies whose mothers had an untreated opioid use disorder.

“Although this study suggests that methadone treatment is a safe option regardless of when it is started in pregnancy, it also highlights that women with opioid use disorders and their children are vulnerable to serious clinical adverse events,” said senior author Dr. Tara Gomes, a scientist at the Li Ka Shing Knowledge Institute of St. Michael’s Hospital and the Institute for Clinical Evaluative Sciences.

“Furthermore, women with an opioid use disorder may be avoiding prenatal care because of a fear of losing custody of their children, which puts both their health and that of their child at higher risk. This is supported by previous research showing that pregnant women with opioid use disorder often forgo their psychiatric and primary care appointments in an attempt to retain guardianship of their unborn child.

“It is therefore imperative that we find a way to make our health-care system more welcoming and accepting of women with opioid use disorders to reduce the stigma and fear experienced by this already marginalized population.”

The study, which was based on an analysis of nearly 2,000 babies whose mothers were treated with publicly funded methadone during pregnancy, suggests that more work is needed to assess long-term outcomes and to investigate barriers to health-care access among pregnant women with opioid use disorders.