years or so, SCBUs have become much more 'parent-friendly', encouraging maximum involvement with the babies. Routine gowns and masks are gone and parents are encouraged to help with care as much as possible. Cuddling and skin-to-skin contact, also known as Kangaroo care, are seen as beneficial for all but the frailest (very tiny babies are exhausted by the stimulus of being handled; or larger critically ill infants). Less stressful ways of delivering high-technology medicine to tiny patients have been devised: sensors to measure blood oxygen levels through the skin, for example; and ways of reducing the amount of blood taken for tests. Some major problems of the NICU have almost disappeared. Exchange transfusions, in which all the blood is removed and replaced, are rare now. Rhesus incompatibility (a difference in blood groups) between mother and baby is largely preventable, and was the most common cause for exchange transfusion in the past. However, breathing difficulties, intraventricular hemorrhage, necrotizing enterocolitis and infections still claim many infant lives and are the focus of many new and current research projects. The long-term outlook for premature babies saved by NICUs has always been a concern. From the early years, it was reported that a higher proportion than normal grew up with disabilities, including cerebral palsy and learning difficulties. Now that treatments are available for many of the problems faced by tiny or immature babies in the first weeks of life, long-term follow-up, and minimising long-term disability, are major research areas. Besides prematurity and extreme low birth-weight, common diseases cared for in a NICU include perinatal asphyxia, major birth defects, sepsis, neonatal jaundice, and infant respiratory distress syndrome due to immaturity of the lungs. In general, the leading cause of death in NICUs is necrotizing enterocolitis. Complications of extreme prematurity may include intracranial hemorrhage, chronic bronchopulmonary dysplasia (see Infant respiratory distress syndrome), or retinopathy of prematurity. An infant may spend a day of observation in a NICU or may spend many months there. Neonatology and NICUs have greatly increased the survival of very low birth-weight and extremely premature infants. In the era before NICUs, infants of birth weight less than 1400 grams (3 lb, usually about 30 weeks gestation) rarely survived. Today, infants of 500 grams at 26 weeks have a fair chance of survival. As of 2022, the world record for the lowest gestational age newborn to survive is held by Curtis Zy-Keith Means, who