The reproductive endocrinology and infertility subspecialist: definition, training, and scope of practice in the United States.

Reproductive endocrinology and infertility (REI) subspecialists are physicians with extensive and specialized training in the diagnosis and treatment of complex reproductive disorders. This unique expertise allows them to provide the highest level of care for patients requiring advanced services for family building, reproductive surgery, and endocrine disorders affecting the female reproductive system. Expertise in reproductive medicine relies on applied physiology and revolves around a fundamental understanding of endocrine physiology and reproductive hormone action at the tissue, cellular, and molecular levels. In addition, an REI's understanding of the fundamentals of study design and data analysis is essential to understand medical literature, adapt to the rapidly changing medical literature, and promote better individualization of care. Reproductive endocrinology and infertility subspecialists are trained surgeons of the female reproductive tract who particularly specialize in minimally invasive surgical approaches, with an emphasis on minimal tissue trauma. REI physicians are trained in the diagnosis and treatment of endocrine, genetic, anatomical, structural, and molecular causes of reproductive disorders, including infertility and advanced fertility options, such as assisted reproductive technologies. This document discusses the training and role of the reproductive endocrinology infertility subspecialist in the United States.