Head Circumference Growth Curves May Be Inaccurate
Curves from large primary care network differ greatly from two recently published curves
MONDAY, Sept. 20 (HealthDay News) -- Head circumference growth curves in a large primary care population appear to differ substantially -- particularly at upper percentiles -- from the two most recently published head circumference growth curves, according to research published online Sept. 20 in Pediatrics.
Carrie Daymont, M.D., of the University of Pennsylvania in Philadelphia, and colleagues compared percentile values and proportion of head circumference observations below the fifth percentile and above the 95th percentile for primary care network (PCN) and existing curves. The PCN was a large, relatively diverse U.S. network. The researchers included 75,412 patients who had a birth weight of at least 1,500 g and a gestational age of at least 33 weeks at birth.
The investigators found that the PCN curves were most similar to curves for the National Center for Health Statistics (NCHS), but quite different from curves of the U.S. Centers for Disease Control and Prevention and the World Health Organization. For PCN, NCHS, CDC, and WHO, the proportion of observations above the 95th percentile was 4.9, 6.2, 8.6, and 14 percent, respectively. The proportion below the 5th percentile was 4.4, 5.1, 2.9, and 2.3 percent, respectively.
"The CDC and WHO head-circumference curves describe different distributions than the clinical measurements in our PCN population, especially for children with larger heads. The resulting percentile misclassification may delay diagnosis in children with intracranial pathology in very young infants and spur unnecessary evaluation of healthy children older than 6 months," the authors write.