Black infants have a somewhat higher risk of cerebral palsy, according to a new study, and the increase appears to be tied to their greater likelihood of being born underweight.

In fact, after taking birth weight into account, blacks are much less likely than whites to be diagnosed with the crippling neurologic disorder, although why that’s the case is a mystery, the scientists said.

“Low birth weight infants have a much higher risk of cerebral palsy,” said Dr. Yvonne Wu, a pediatric neurologist at the University of California, San Francisco who led the study. She told Reuters Health, “If we could eliminate the racial disparity in low birth weight deliveries, then we would also eliminate the differences in cerebral palsy between blacks and whites.”

“We need these big population studies to get at those kind of details,” said Dr. Nancy Murphy, a pediatrician at the University of Utah in Salt Lake City, and chair of the American Academy of Pediatrics Council on Children With Disabilities.

The new research suggests that efforts to improve prenatal care among black mothers, particularly teens, might reduce the incidence of cerebral palsy among blacks, according to the researchers. Women who receive early and high-quality prenatal care tend to have healthier babies than those who don’t get the checkups.

“We found that women who received prenatal care had a lower risk of having a child with cerebral palsy,” Wu said. “However, we don’t know whether the prenatal care itself protects women from having a child with cerebral palsy, or whether women who receive prenatal care differ in some other way that reduces the risk of having a child with cerebral palsy.”

For the study, published online today in the journal Pediatrics, Wu and her colleagues analyzed medical records of 6.2 million births in California between 1991 and 2001. Among them, about 8,400 infants had been diagnosed with cerebral palsy, for a rate of 1.4 cases per 1,000 live births.

That’s somewhat less than previous estimates, which have put the prevalence of cerebral palsy at between 2 and 2.5 cases per 1,000 live births.

The lower rate reflects the fact that the California researchers did not include children with mild cases of cerebral palsy who did not qualify for state services, Wu explained.

Of the nearly 8,400 babies with cerebral palsy, 758 were black, 2,878 were white, 3,963 were Hispanic and 656 were Asian.

Blacks were about 30 percent more likely than whites to have cerebral palsy, the researchers found. Hispanics had roughly the same odds as whites, while Asians appeared to be least likely to be diagnosed with the condition.

Babies born underweight or premature were up to 24 times more likely to be diagnosed with cerebral palsy, the researchers said, and both risk factors were much more common among blacks. But after accounting for low birth weight, blacks were between 21 percent and 29 percent less likely than whites to be diagnosed with cerebral palsy, according to the researchers.

Women who did not have prenatal care had more than twice the typical chance of giving birth to a baby with cerebral palsy, the researchers found. Those who did not graduate from high school also had a higher risk.

Although Wu said her findings point to a possible role for prenatal care in preventing cerebral palsy among blacks, an example from recent history might temper optimism for the strategy. In the 1970s, doctors began advocating that women use electronic fetal monitors as a way to prevent cerebral palsy.

“The thinking was that if you could detect fetal distress by monitoring the baby’s heart rate prior to delivery, you could perform a cesarean section earlier, and thereby prevent brain injury. However, even though electronic fetal monitoring leads to about 40 percent more cesarean sections, it has not been effective in preventing cerebral palsy,” she said.

Teasing out the impact of prenatal care on infant health, added Murphy, who was not involved in the study, is “exquisitely complicated.”

SOURCE: bit.ly/dK6r16 Pediatrics, online February 21, 2011