Delivery at the threshold of viability (23+0 weeks to 24+6 weeks of gestation) is a major medical and ethical challenge. It should be preceded by the best possible advice from a multidisciplinary neonatal and obstetric team, which informs parents fully, seeks to achieve a consensus on the best way forward and provides the best care for the mother and neonate. There is international consensus that at 22 weeks of gestation there is no hope of survival, that up to 22+6 weeks is considered to be the cut–off of human viability and for week 25+0 onwards there is also a general agreement that active management should be offered. Delivery between these two gestational age limits is the most challenging.
Given the importance of reducing the morbidity associated with extreme prematurity, it is essential that obstetricians optimise all aspects of the peridelivery period at the threshold of viability. Inevitably this includes accurate counselling of likely outcomes, prediction of impending preterm delivery, transferring the woman to an appropriate perinatal unit, promoting fetal maturation, preventing cerebral palsy, as well as optimising the timing, site and mode of delivery while minimising the risk of infection and neurological injury.
This paper looks at the existing evidence base covering issues specific to the obstetric perinatal management of extremely preterm infants born spontaneously between 23+0 and 24+6 weeks of gestation and provides an opinion on the clinical management of women who are pregnant who are in preterm labour at the extreme of infant viability.