Changing Prevalence of Cerebral Palsy Coleen Boyle, Ph.D. National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention

What impacts the rate of CP in very preterm infants? Birth rate (live births/1000) Birth weight/preterm birth distribution Survival in preterm/vlbw infants Prevalence of CP in preterm survivors

How have each of these factors changed overtime?

Factor #1: Birth rate Birth rate has decrease since 1960s, but number of reproductive age women has increased Changes in birth rate do not change rate; but will change absolute number of case children

Cerebral Palsy in Atlanta, Atlanta, No. live birth/yr No. case children Cp rate 21, , ,

Factor #2: Birthweight/preterm birth distribution The rate of very preterm births (<32 weeks GA) in the U.S. has increased 9% from 1981 to 1999 (1.81% of all births in 1981 to 1.98% in 1999) Whites – 12% ( ) Blacks – unchanged ( )

Factor #3: VLBW/Preterm Infant Survival Critical factor because this group is at highest risk of CP and other disability

Survival in Infants <1500g, Altanta,

Low Birth Weight and DD Birth Weight (gms) Survivors No. Any DD Rate/100 < , ,1780.8

Overall Disability at 30 Months Woods et al, 2000

Woods et al, RESULTS Development – 19% with Bayley >3 SD ; 11% 2-3 SD Neuromotor – 10% with severe disabilities 14% other disabilities Sensory- 2% blind; 2% deaf; 5% no speech

Factor # 4: Prevalence of CP in preterm survivors Impact of prenatal factors: role of inflammation, infection Impact of antenatal care/intervention? –corticosteriods; surfactant; others

Source: Stanley, Blair & Alberman, 2000 Rates of CP in Neonatal Survivors

Source: Stanley, Blair & Alberman, 2000

Source: Stanley, Blair + Alberman, 2000

Source: Stanley, Blair & Alberman, 2000

Source: O’Shea 1998 Pediatrics

<1000 g g Total <1000 g g Total <1000 g g Total No. of children with CP No. of singleton survivors <1500 g Prevalence per 1000 survivors <1500 g Table. Prevalence of moderate or severe CP in singleton weighing < 1500 g born in 4 northern California counties Source: Grether: J Pediatr, 136; 2000:133

% DyingCPBlindness Bayley MDI <68 Outcome at 1 yr in infants weighing 501 – 800 gm, North Carolina Source: O’Shea et al. Pediatrics 1998:101

Percent % Survivors and Prevalence of CP in Infants <1500 g, Atlanta, births

Prevalence of CP <1500 g survivors, Atlanta, 1975 –1991, by race Percent white black

Characteristics of CP in infants <1500 g, Atlanta, % Isolated CP% Spastic diplegia 1975 – –

Trends in CP – Conclusions Factor 1: Birth rate stable; rise in the number of reproductive age women Factor 2: Proportion of very preterm births has increased Factor 3: Infant mortality in very preterm infants continues to improve Factor 4: Increase - mid to late 1980’s; decrease in early 1990’s