Book excerpt: This issue of Obstetrics and Gynecology Clinics of North America deals with the timely subject of substance use during pregnancy. Alcohol, tobacco, and illicit drug use is prevalent among reproductive-age women. Even though a reduction in use often occurs during pregnancy, many women continue to use substances until a pregnancy is either actually diagnosed or well underway.This issue consists of a well-qualified team of obstetricians-gynecologists, psychiatrists, and family physicians, focusing on various issues related directly to pregnancies complicated by substance use. Topics of interest include epidemiology and screening for hazardous and harmful substance use, teratogenic risks, psychiatric comorbidities, comprehensive treatment approaches before and after delivery, fetal surveillance, and team-based perinatal management. Particularly new information relates to prescribing buprenorphine, neonatal abstinence syndrome, and adolescent substance use.