Foetal to neonatal transition — what can go wrong?

Abstract 

Failure of the foetus to make a successful transition from the intrauterine environment can be life threatening. Prompt recognition of problems can enable critical, life-saving interventions to take place. Whilst there are numerous adaptations of the newborn at birth, this article focuses on those which are the most common and/or clinically urgent, and describes not only the conventional treatments but also emerging therapies. The article therefore covers maladaptive processes in the normal newborn, not those with genetic or other congenital problems which cause maladaptation due to the underlying disease. Likewise, it is outside the scope of this article to discuss neonatal jaundice, as it is arguably not a maladaptation, and may also not be the ‘design flaw’ that it has previously been considered to be, as bilirubin may have a physiological role as the main antioxidant in the newborn in the first week of postnatal life. I have described five neonatal conditions: transient tachypnoea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension, which can all cause significant hypoxaemia, patent ductus arteriosus which is usually not clinically significant but is common and often causes considerable parental anxiety, and transient hyperinsulinaemia which can cause profound hypoglycaemia.

It is recommended that the reader has an understanding of the normal physiological adaptive processes which are described in greater detail in the accompanying article.

Keywords: Failure of postnatal adaptation, hyaline membrane disease, neonatal hyperinsulinaemia, persistent foetal circulation (PFC), persistent pulmonary hypertension of the newborn (PPHN), respiratory distress syndrome (RDS), surfactant