We read with great interest the article by Bell et al. The authors suggest that “detoxification of opiate-addicted pregnant patients is not harmful” based on a retrospective analysis of 301 opioid-dependent pregnant women at a single site.

We write to express our concern about the approach of detoxifying from opioids during pregnancy. The center “actively promoted opiate detoxification during pregnancy” because of concerns about the cost of neonatal abstinence syndrome treatment. Neither North American nor international clinical guidelines support this as a first-line approach.

Only patients who were fully detoxified were included, and there was still a relapse rate of 36% overall, with treated neonatal abstinence syndrome in 31% of neonates. There is a notable lack of detailed data on preterm birth rates and rates of intrauterine growth restriction for each of the subgroups.

The authors focus on measurable indicators of fetal well-being in a small sample with limited power to detect rare, but serious, fetal or maternal adverse outcomes. Detoxification may put the woman at an increased risk of overdose death. In countries with robust investigation of maternal deaths, women with a history of substance abuse are over-represented in mortality statistics, with some maternal deaths relating to overdose subsequent to opioid detoxification. A Norwegian study that assessed mortality risk subsequent to inpatient detoxification in a nonpregnant population found that the elevated risk of dying from an overdose within the first 4 weeks of discharge was so dramatic that preventable measures should be instituted. Opioid users have been found to have a higher risk of in-hospital maternal death in a large US all-payer inpatient database study with rates of 0.8 and 0.1 per 1000 for opioids users and nonusers, respectively (adjusted odds ratio, 3.69; 95% confidence interval, 2.32–5.87).

There are real and substantial maternal and neonatal risks with the authors’ proposed approach of opioid detoxification in pregnancy. The size of the study limited the potential to report on rare adverse outcomes such as stillbirth and overdose deaths. The reported study does not adequately support the author’s conclusions. If this approach were to be adopted widely, extensive harm could occur.