Extreme Immaturity

Abstract

The article¹in this issue of AJDC entitled "What Is the Lower Limit of Viability?" raises a question that truly exemplifies the evolution of neonatology. This question has been asked in the 1950s, 1960s, 1970s, and 1980s, and in each decade the answer has changed. The answers have changed first because of technology. In successive steps, the equipment has been adapted to and developed for smaller and less mature infants. Second, the skills, and third, the attitudes of physicians and nurses have also changed. See also p 783. These factors have gradually become incorporated as "standards of acceptable practice for very-low-birth-weight infants." In spite of these standards, however, there have always been exceptions—the less than 1,500 g survivor in the 1950s, the less than 1,000-g survivor in the 1960s, and the less than 500-g survivor today. In every era, these cases tend to provoke our imagination and keep us reaching