Paediatrics: Birth at the limit of viability

2021-03-09 12:00 AM

WHO defines the perinatal period as starting at 22wks gestation, which is realistically the earliest gestation of viability.

Birth at the limit of viability

WHO defines the perinatal period as starting at 22wks gestation, which is realistically the earliest gestation of viability. In the UK threshold viability is generally accepted to be when birth is between 22 and 25 completed weeks gestation, typically 500–1000g birth weight.

Management before birth

As gestation falls, the likelihood of mortality and serious long-term dis-ability increases. When preterm birth at threshold viability is threatened there should be close collaboration between paediatrician, obstetrician, midwife, and family.

Unless delivery is precipitate a senior paediatrician should meet parents before birth to assess and do the following:

  • Ascertain whether estimate of gestation is likely to be reliable.
  • Give relevant information.
  • Outline potential problems.
  • Outline possible management (including option of not resuscitating).
  • Describe relevant survival and disability rates.
  • Parents should fully participate in any decision about the appropriateness of any later attempted resuscitation.

Management at birth

  • <22wks gestation: rarely suitable for resuscitation, but it may still bebeneficial for a senior paediatrician to attend birth to reassure parents and support staff in provision of comfort care.
  • 22–25wks gestation: a senior obstetrician and paediatrician should bepresent to assess size, maturity, and condition of the newborn and then manage appropriately. If an infant appears viable, respiratory support should be given. External cardiac massage or resuscitation drugs are not generally considered appropriate. If junior doctors are present alone at such a delivery full resuscitation should be started and continued until a senior paediatrician arrives and makes an assessment. If parents do not wish life-sustaining care in an infant born before 25wks their view should be respected and taken into account. However, if the infant appears unexpectedly vigorous or more mature, full treatment should be started.

If resuscitation is withheld on a delivery ward the infant should be kept warm and comfortable, as well as offered to parents to cuddle.

Management after birth

Clinical progress after the initial resuscitation and further discussion with the parents will dictate whether it is appropriate to continue or withdraw life-sustaining treatment. Where doctors and parents, or parents themselves, cannot agree as to the best or most appropriate management it is almost always best to continue as the situation will become clearer with time and agreement is usually then reached.