Intrauterine exposure to maternal opioid maintenance treatment and associated risk factors may impair child growth.

Aim: How maternal opioid maintenance treatment (OMT) affects children is under-researched. This population-based registry study investigated child growth and somatic health following intrauterine exposure to this treatment.

Methods: Children born between 1 March 2011 and 30 May 2021 to mothers who used buprenorphine, buprenorphine-naloxone, or methadone throughout their pregnancies were followed for 2 years at the Helsinki University Hospital, Finland.