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Published on: November 20, 2015
Increasing prevalence of cerebral palsy among very preterm infants: a population-based study
Michael J Vincer1, Alexander C Allen, K S Joseph
1Perinatal Follow-up Program of Nova Scotia, Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada. vincer@dal.ca
Insights
Declines in infant mortality have coincided with a substantial increase in cerebral palsy rates among very preterm infants. This trend suggests a potential link between improved survival and the occurrence of cerebral palsy in this vulnerable population.
Area of Science:
- Neonatalogy
- Pediatric Neurology
- Public Health
Background:
- Declining neonatal and infant mortality rates are a significant public health achievement.
- The impact of these survival improvements on the long-term neurological outcomes of preterm infants remains an area of active investigation.
- Cerebral palsy (CP) is a major concern in very preterm infants, affecting neurological development.
Purpose of the Study:
- To investigate temporal trends in the prevalence of cerebral palsy (CP) among very preterm infants.
- To examine the relationship between changes in infant mortality and the occurrence of CP.
- To identify factors associated with temporal changes in CP rates in this cohort.
Main Methods:
- A population-based cohort of very preterm infants (24-30 weeks gestational age) born between 1993-2002 in Nova Scotia was studied.
- Infant survival and cerebral palsy rates were analyzed by year and two 5-year periods (1993-1997 and 1998-2002).
- Logistic regression analyses identified factors associated with temporal changes in CP rates.
Main Results:
- Infant mortality decreased significantly from 256 to 114 per 1000 live births between 1993 and 2002.
- Cerebral palsy rates in very preterm infants increased from 44.4 to 100.0 per 1000 live births during the same period.
- Factors associated with increased CP included low gestational age, postnatal dexamethasone, patent ductus arteriosus, severe hyaline membrane disease, delivery room resuscitation, and intraventricular hemorrhage; antenatal corticosteroid use was associated with lower CP rates.
Conclusions:
- Cerebral palsy has substantially increased among very preterm infants.
- This increase appears to be associated with, and possibly a consequence of, significant declines in infant mortality.
- Further research is needed to understand the mechanisms linking improved survival and CP in this population.
Objectives:
It is unclear whether declines in neonatal and infant mortality have led to changes in the occurrence of cerebral palsy. We conducted a study to examine and investigate recent temporal changes in the prevalence of cerebral palsy in a population-based cohort of very preterm infants who were 24 to 30 weeks of gestational age.
Methods:
A population-based cohort of very preterm infants who were born between January 1, 1993, and December 31, 2002, was evaluated by the Perinatal Follow-up Program of Nova Scotia. Follow-up extended to age 2 years to ascertain the presence or absence of cerebral palsy and for overall survival. Infant survival and cerebral palsy rates were compared by year and also in two 5-year periods, 1993-1997 and 1998-2002. Logistic regression analyses were used to identify factors that potentially were responsible for temporal changes in cerebral palsy rates.
Results:
A total of 672 liveborn very preterm infants were born to mothers who resided in Nova Scotia between 1993 and 2002. Infant mortality among very preterm infants decreased from 256 per 1000 live births in 1993 to 114 per 1000 live births in 2002, whereas the cerebral palsy rates increased from 44.4 per 1000 live births in 1993 to 100.0 per 1000 live births in 2002. Low gestational age, postnatal dexamethasone use, patent ductus arteriosus, severe hyaline membrane disease, resuscitation in the delivery room, and intraventricular hemorrhage were associated with higher rates of cerebral palsy, whereas antenatal corticosteroid use was associated with a lower rate.
Conclusion:
Cerebral palsy has increased substantially among very preterm infants in association with and possibly as a consequence of large declines in infant mortality.
