Women with opioid use disorder are at increased risk of other medical complications of pregnancy. Providing care for such complex patients requires the ability to 1) acknowledge addiction as a chronic disease, 2) incorporate the altered physiology of pregnancy, and 3) devise a treatment plan that can effectively manage acute conditions. A basic tenet of care is rooted in experience, rather than evidence, but includes stabilization of opiate use disorder (OUD) as a primary goal of management of other medical complications of pregnancy. Proceeding with treatment for other medical conditions will be suboptimal without stabilization of the underlying chronic disease process. This chapter outlines some associated medical complications of OUD both in general and some of which are unique to pregnancy: infectious diseases, soft tissue infections, endocarditis, cholestasis of pregnancy, and overdose.