[Obstetrical considerations regarding marginal fetal viability of very early premature infants]

As a result of the impressive progress in perinatal medicine the frontier of extrauterine viability has been shifted to a continuously decreasing gestational age. Optimal results require a close collaboration between obstetrician and neonatologist following well defined protocols. The quality of interdisciplinary efforts in perinatal medicine is not only measured by survival rates but by the number of survivors with good chances of normal development. Before 24 weeks survival rate drops below 10% and more than half of the few survivors show signs of more or less severe handicaps. Interventional medicine, be it prenatally, during or after birth, is not recommended. Comfort care and support is given to the parents as well as the infant after birth. Beyond 26 weeks chances of survival rapidly increase above 50% while the rate of handicapped among the survivors drops below 50%. Starting with 26 weeks full monitoring of the fetus and operative interventions for delivery of the fetus together with expert neonatal treatment to assure optimal survival are recommended. In the grey zone of 24 and 25 weeks management must be individualized considering the special circumstances of the individual case and taking into account the basic expectations of the parents. Prenatally the most common clinical scenarios can be assigned to one of three categories, which are described in some detail.