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Dose-dependent relationship between acidosis at birth and likelihood of death or cerebral palsy
Rod Kelly1,2, S M Ramaiah3, Helen Sheridan4
1Scottish Specialist Transport and Retrieval Service, Royal Infirmary of Edinburgh, Edinburgh, UK.
Insights
Severe acidosis in newborns, indicated by low pH or high base deficit within an hour of birth, is linked to increased risks of poor outcomes. This study confirms a dose-dependent relationship between acidosis severity and adverse neonatal and neurodevelopmental results.
Area of Science:
- Neonatalogy
- Perinatal Medicine
- Pediatric Neurology
Background:
- Infant acid-base status at birth offers insights into neonatal condition.
- Umbilical cord blood pH <7.0 or base deficit ≥12 mmol/L indicates increased adverse outcome risk.
- Prognostic value of acidosis degree needs clarification due to varied study parameters.
Purpose of the Study:
- To investigate the relationship between the degree of acidosis at birth and neonatal/neurodevelopmental outcomes.
- To clarify the prognostic value of acidosis severity in infants born at ≥35 weeks gestation.
- To establish dose-dependent relationships between acidosis markers and adverse outcomes.
Main Methods:
- Retrospective review of clinical data for infants born ≥35 weeks gestation (2005-2013).
- Inclusion criteria: lowest recorded pH <7 or highest base deficit ≥12 mmol/L (cord or neonatal blood gas within 1 hour).
- Neurodevelopmental outcomes for infants with encephalopathy were collected from follow-up data.
Main Results:
- 506 out of 56,574 infants met inclusion criteria (0.9%).
- Adverse outcomes increased with worsening acidosis: combined death/cerebral palsy rates were 3%, 10%, 40% for pH 6.9-6.99, 6.8-6.89, <6.8.
- Rates were 8%, 14%, 59% for base deficit 12-15.9, 16-19.9, ≥20 mmol/L, respectively.
Conclusions:
- A dose-dependent relationship exists between acidosis degree within one hour of delivery and adverse outcomes.
- Worsening acidosis correlates with higher likelihood of adverse neonatal and neurodevelopmental outcomes.
- Findings support the prognostic significance of acidosis severity in term and preterm infants.
Background:
The acid-base status of infants around birth can provide information about their past, current and future condition. Although umbilical cord blood pH <7.0 or base deficit ≥12 mmol/L is associated with increased risk of adverse outcome, there is uncertainty about the prognostic value of degree of acidosis as previous studies have used different variables, thresholds, outcomes and populations.
Methods:
Retrospective review of routinely collected clinical data in all live-born inborn infants of 35 weeks gestation or more delivered between January 2005 and December 2013 at the Simpson Centre for Reproductive Health, Edinburgh, UK. Infants were included if their lowest recorded pH was <7 and/or highest base deficit ≥12 mmol/L on either umbilical cord blood and/or neonatal blood gas within 1 hour of birth. Neurodevelopmental outcome of the infants with encephalopathy was collected from the targeted follow-up database.
Results:
56 574 infants were eligible. 506 infants (0.9%) met inclusion criteria. Poor condition at birth and all adverse outcomes increased with worsening acidosis. Combined outcome of death or cerebral palsy was 3%, 10% and 40% at lowest pH of 6.9-6.99, 6.8-6.89 and <6.8, respectively, and 8%, 14% and 59% at a base deficit of 12-15.9, 16-19.9 and 20 mmol/L or more, respectively.
Conclusions:
There is a dose-dependent relationship between the degree of acidosis within an hour of delivery, and the likelihood of adverse neonatal and later neurodevelopmental outcome in infants born at 35 weeks gestation or more.
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