Occurrence of Cerebral Palsy in South Carolina Declined from 1996 to 2009

The occurrence of cerebral palsy in South Carolina decreased significantly from 1996 to 2009, but was higher in very underweight infants, non-Hispanic black infants, and boys, a study shows.

The study, “Decreasing prevalence of cerebral palsy in birth cohorts in South Carolina using Medicaid, disability service, and hospital discharge data, 1996 to 2009,” was published in the journal Developmental Medicine & Child Neurology.

Cerebral palsy (CP), the most common cause of motor disability in children, is mainly caused by perinatal brain injury due to oxygen deprivation. Monitoring its burden and occurrence is highly important to better understand its risk factors and establish potential associations between obstetrical and pediatric clinical practices and development of cerebral palsy.

This is even more relevant for premature and underweight newborns, who are at a greater risk of developing cerebral palsy.

Population-based registries in Australia and Europe have suggested that CP occurrence is decreasing over time, but a similar registry is lacking in the U.S., probably due to large population sizes, poor collaboration between institutions, and decentralized medical and social systems.

Researchers at Medical University of South Carolina and San Diego State University have now evaluated the occurrence of CP in the first four years of age from 1996 to 2009 in South Carolina, using data from Medicaid, the state Department of Disabilities and Special Needs, and hospital discharges.

They also analyzed the occurrence by birth weight, gestational week at birth (premature or standard birth), ethnicity/race, and gender.

Among the 755,433 live births that occurred during that period, the team identified 2,080 children with a CP diagnosis, and Medicaid contributed with 51% of exclusive CP cases.

The analysis showed that while live births in South Carolina increased from 48,622 (1996) to 59,677 (2008), CP cases decreased from a peak of 178 (1998) to a low of 122 (2006).

Also, 76 (3.7%) of children with CP died before age 4, with the largest percentage (34.2%) occurring around age 1.

Excluding cases of early death, the total CP prevalence in South Carolina from 1996 to 2009 was 2.8 cases per 1000 live births, 13.9 per 1000 underweight (less than 2499 g) births, 46 per 1000 very underweight (less than 1,500 g) births, 53 per 1,000 very underweight one-year survivors, and 65.5 per 1,000 extreme premature (less than 28 weeks) births.

These results revealed that underweight and extreme premature newborns had a higher CP prevalence than those born within a normal weight and time, which supported the association between premature and underweight newborns and the development of CP.

A significantly higher frequency of CP also was found among non-Hispanic black infants (3.7 cases per 1,000 births) compared to non-Hispanic white infants (2.3 per 1,000) and among boys (3.1 per 1,000) compared with girls (2.4 per 1,000).

Over time, the total CP frequency rate declined significantly, ranging from 3.6 cases per 1,000 births (1996) to 2.1 per 1,000 (2006). This reduction trend was consistent and significant across all birthweights, gestational weeks, ethnicities/races, and gender, except for Hispanic infants, whose CP prevalence (2.0 per 1,000) was low and stable over time.

The team noted that additional studies are required to validate this type of approach, which has the potential to be less expensive than directly analyzing individual patient data.

“Our methods can serve as a stepping stone to establish public health surveillance systems, to rapidly evaluate clinical practice changes, and [to better understand the causes of] perinatal brain injury,” researchers wrote.