Background
Despite recent advances in perinatal care, neonatal hypoxic-ischemic encephalopathy
remains one of the most common causes of neonatal morbidity and mortality. The trends
for prevalence and mortality of neonatal hypoxic-ischemic encephalopathy have not
been examined in the era of therapeutic hypothermia in the United States.
Objective
This study aimed to determine (1) the overall and gestational age–specific (35–36,
≥37, and >42 weeks) trends of hypoxic-ischemic encephalopathy prevalence and use of
therapeutic hypothermia, (2) the trends of mortality in association with hypoxic-ischemic
encephalopathy, (3) the confounding variables associated with hypoxic-ischemic encephalopathy,
and (4) the clinical outcomes of neonates with hypoxic-ischemic encephalopathy.
Study Design
This study used National Inpatient Sample datasets from 2010 to 2018. Moreover, the
study included infants with a gestational age of ≥35 weeks with a documented hypoxic-ischemic
encephalopathy diagnosis (mild, moderate, severe, or unspecified). We calculated trends
in hypoxic-ischemic encephalopathy prevalence and the use of therapeutic hypothermia
using chi-squared testing. Furthermore, this study used logistic regression models
to control for confounders.
Results
A total of 32,180,617 infants were included, of which 31,249,100 were term (gestational
age of ≥37 weeks) and 931,517 were late preterm (gestational age of 35–36 weeks).
Hypoxic-ischemic encephalopathy prevalence slightly increased from 0.093% in 2010–2012
to 0.097% in 2016–2018 (P=.01) in term infants and did not significantly change in late preterm infants (P=.20). There were 6235 term infants (20.8%) and 449 late preterm infants (21.1%) with
hypoxic-ischemic encephalopathy who were managed with therapeutic hypothermia. The
use of therapeutic hypothermia in both term and late preterm infants has increased
over the years (P<.01). The mortality rate with hypoxic-ischemic encephalopathy decreased over time
from 11.5% to 12.3% between 2010 to 2012, and from 8.3% to 10.6% betweenn 2016 to
2018 (P<.01). The factors with the strongest association with hypoxic-ischemic encephalopathy
were placental infarction or insufficiency (odds ratio, 144; 95% confidence interval,
134–157), placental abruption (odds ratio, 101; 95% confidence interval, 91–112),
cord prolapse (odds ratio, 74; 95% confidence interval, 65–84), and maternal anemia
(odds ratio, 26; 95% confidence interval, 20–37).
Conclusion
Hypoxic-ischemic encephalopathy prevalence in neonates essentially remained the same
at 1 per 1000 live births. The use of therapeutic hypothermia increased, and the mortality
rate decreased in infants with hypoxic-ischemic encephalopathy. The identification
of hypoxic-ischemic encephalopathy–associated factors should promote increased vigilance
to optimize newborn outcomes.
Key words
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Article Info
Publication History
Published online: June 08, 2022
Accepted:
June 2,
2022
Received in revised form:
June 1,
2022
Received:
April 3,
2022
Publication stage
In Press Journal Pre-ProofFootnotes
H.A. and M.M. are both senior authors.
The authors report no conflict of interest.
Cite this article as: Acun C, Karnati S, Padiyar S, et al. Trends of neonatal hypoxic-ischemic encephalopathy prevalence and associated risk factors in the United States 2010–2018. Am J Obstet Gynecol 2022;XX:x.ex–x.ex.
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