Neonatology is a subspecialty of pediatrics that consists of the medical care of newborn infants, especially the ill or premature newborn. It is a hospital-based specialty, and is usually practiced in neonatal intensive care units (NICUs). The principal patients of neonatologists are newborn infants who are ill or require special medical care due to prematurity, low birth weight, intrauterine growth restriction, congenital malformations (birth defects), sepsis, pulmonary hypoplasia or birth asphyxia. While high infant mortality rates were recognized by the British medical community at least as early as the 1860s, modern neonatal intensive care is a relatively recent advance. In 1898 Dr. Joseph DeLee established the first premature infant incubator station in Chicago, Illinois. The first American textbook on prematurity was published in 1922. In 1931 Dr A Robert Bauer invented the first incubator to combine heat, and oxygen, as well as humidity while at Henry Ford Hospital.