[Limitations of extreme prematurity].
The extreme limit of viability in premature infants, related to pulmonary maturity, cerebral structuration and the capacity to maintain homeostasis and metabolic functions is approximately 23-24 weeks of gestation. Currently at 25-26 weeks, with a birth-weight of 600 g, the probability of survival at 1 year is 50%; at 27-28 weeks 1 year survival rises to 60-80% and at 29 weeks reaches 90%. Motor, sensorial and intellectual or psychological sequellae are seen in approximately 20% of the infants born after less than 27 weeks gestation. Over the last twenty years the gain in the number of normal surviving infants has been multiplied by 20, and therefore, despite a decrease in the percentage of children with sequellae, the total number of handicapped children has also increased. From an ethical point of view, every newborn, whatever his birthweight, gestational age or clinical distress is a human being and has a right to the preservation of his potential for survival. Although current legislation sets a limit of 22 weeks or 500 g for declaration of birth, the real question is to determine the medically ethical limit for intensive care.