Slightly Premature Babies At Risk For Cerebral Palsy
Researchers have long known that babies born many weeks or months before their due dates are at an elevated risk of cerebral palsy, a lifelong condition that can cause mild to severe physical disability.
Now, new research published in the Journal of the American Medical Association finds that infants who arrive just a little early -- at 37 or 38 weeks' gestation -- are at risk too.
"What we're observing is that babies born a little before 40 weeks or a little afterwards have higher risk too," says study co-author Allen Wilcox of the National Institute of Environmental Health Sciences.
The study found that a baby delivered at 38 weeks -- two weeks shy of the mother's due date of 40 weeks -- is twice as likely as a full-term baby to develop cerebral palsy. The risk is even greater for babies born more prematurely -- up to 14 times higher for babies born at 33 weeks' gestation. The study is based on data collected in a Norwegian birth registry that includes more than 1.6 million births between 1967 and 2001, and it fits with a flurry of recent studies suggesting that babies born a little early are more prone to a range of complications including feeding and respiratory problems.
Each year about 10,000 babies in the U.S. develop cerebral palsy in the months after their birth. In some cases, children may struggle to move one limb or one side of their bodies. In more severe cases, children come to rely on wheelchairs to move around.
There is no cure for the disability, but increasingly there is a focus on early intervention to prevent the development of cerebral palsy in infants. Researchers, for instance, are studying the effectiveness of using magnesium sulfate at the time of delivery to protect the brain of preemies. There are also experiments using head cooling -- lowering the infant's body temperature a couple of degrees for a period of several days.
"There are some possibilities of things you could do to prevent cerebral palsy by intervention," says Nigel Paneth, a professor of epidemiology and pediatrics at Michigan State University.
Early Physical Therapy
Evidence shows that physical therapy is helpful in ameliorating some physical disabilities in children with cerebral palsy, which is normally recognized by parents and caregivers when the children are between 6 and 8 months old.
Kim Falks first noticed the difference in her twin boys when one son, Andrew, started to sit up and crawl. "Ethan was not able to do those things" Falks says.
After Ethan was diagnosed with cerebral palsy at 18 months of age, she started therapy for him and enrolled him in a physical therapy study at the University of Nebraska Medical Center. The study was designed to determine how best to help kids with cerebral palsy learn to sit up independently.
"We've certainly seen improvement with his head control and with him being able to keep his head up," says Falk. Therapists have found that exercises aimed at building trunk and core muscles can help build the strength children need to sit and eat independently.
And doing the exercises more than once a week is important too -- the study compared the effectiveness of one session per week with that of several sessions.
"The children who had therapy two times a week seemed to make further progress," says Regina Harbourne, a professor of physical therapy at the University of Nebraska Medical Center's Munroe-Meyer Institute. "A greater percentage of the kids were crawling and had more variety of movements."
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The most common cause of severe physical disability among children is cerebral palsy. Each year, about 10,000 infants in the U.S. are born with it. The condition can make even simple movements, sitting up or moving an arm, a struggle. There's no cure, but increasingly, doctors are focused on early therapy and interventions.
NPR's Allison Aubrey reports on who's at risk of cerebral palsy and what can be done to help.
ALLISON AUBREY: When Kim Falk was pregnant with twin boys eight years ago, her doctors had given her a heads-up that her babies would likely be born a little early. She just never anticipated how early. They arrived 11 weeks premature, which put them at risk of many complications, including cerebral palsy.
Ms. FALK(ph): We did know the risk of, you know, me having preterm labor, but nobody had really educated us on the fact that this would happen.
AUBREY: At first, both boys seemed relatively healthy for preemies, but then Kim learned that one of her twins, Ethan, had suffered bleeding in the brain. And by six months, she noticed that Ethan wasn't moving nearly as much as his brother.
Ms. FALK: When Andrew was starting to try to crawl and sit up, I mean, Ethan was not able to do those things.
AUBREY: Ethan was diagnosed with cerebral palsy when he was about 18 months old. And experts say, given how prematurely he was born, his risks were much higher - at least 14 times greater than a full-term baby.
Dr. JANET SOUL (Neonatal Neurologist, Children's Hospital Boston): That's true. Every week that a baby is born earlier increases their risk of cerebral palsy.
AUBREY: Janet Soul is a neonatal neurologist at Children's Hospital in Boston. She says the link between premature birth and cerebral palsy has been known for decades. But the lingering question is why?
In the case of severe preemies, it seems clear that the condition develops as a result of the early birth - given how underdeveloped the brain and central nervous systems are. But a new study published this week in the Journal of the American Medical Association suggests that even babies born just a few weeks early are at higher risk of cerebral palsy too.
Dr. SOUL: This new study does show that children who are born just two or three weeks earlier than term age have a higher risk of cerebral palsy.
AUBREY: This is a brand-new finding, but Soul says she's not really surprised. It fits with a spate of new studies showing that babies born just a few weeks shy of the normal 40-week gestation period are more prone to a range of complications, including feeding and respiratory problems.
Dr. SOUL: Because I think, in general, biology usually gets it right. And so we know that 40 weeks is the usual time for delivery. And so it probably shouldn't be that surprising that the farther you deviate from that, the more trouble you're likely to have.
AUBREY: Experts say these findings may give pause to obstetricians and moms-to-be who might try to schedule or induce a birth a little early just for convenience's sake. But when babies arrive early on their own, which is often the case with twins and multiples and do develop cerebral palsy, there's increasing evidence that starting physical therapy early helps.
Mom Kim Falk enrolled her son Ethan in a physical therapy study at the University of Nebraska two years ago.
Ms. FALK: We have certainly seen improvement with his head control and being able to keep his head up.
AUBREY: Some children with cerebral palsy have trouble moving just one side or one limb. For Ethan, whose case is more severe, physical therapists have found that repeated exercises to build trunk and core muscles beginning at about 12 months of age helps build the strength needed to sit and eat independently.
Allison Aubrey, NPR News. Transcript provided by NPR, Copyright National Public Radio.
