Hb H disease is a moderate to severe form of alpha-thalassemia (alpha-thal). Patients with Hb H disease may become symptomatic, especially during infections and pregnancy, and may require transfusions. Herein, we present a 16-year-old female with Hb H disease who was initially diagnosed during adolescent pregnancy and was found to carry the -alpha(3.7)/-(alpha)(20.5) deletions. The relatively mild presentation of this case highlights the milder phenotypic consequences of deletional alpha mutations. The case describes the screening and management of pregnancy with Hb H disease. Additionally, this case demonstrates that screening of some undiagnosed inherited blood disorders is important during pregnancy.