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It was long assumed that brain injuries in newborns resulted from insufficient oxygen during labor or delivery. Distressed parents often blamed doctors, a belief that spawned countless malpractice suits and prompted many obstetrician-gynecologists to abandon the delivery room.
The truth is far more complex, according to an important new report by a committee of experts in obstetrics, pediatrics, neurology and fetal-maternal medicine. Many conditions that occur during or even before pregnancy can lead to neurological damage to full-term babies.
The document, called Neonatal Encephalopathy and Neurologic Outcome, updates a version published in 2003 that focused on oxygen deprivation, or asphyxia, around the time of birth. The new report, which highlights significant advances in diagnosis and treatment in the decade since, was published by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics. Brain injuries affect about three in 1,000 babies born full-term in the United States, but only half of these cases are linked to oxygen deprivation during labor and delivery, according to the new report. And even in those instances, a problem that occurred long before birth might have exaggerated the effects of a reduced oxygen supply that would have not otherwise caused a lasting brain injury.
According to the 2003 report, fewer than 10 percent of children with cerebral palsy, the most severe such brain injury, showed signs of asphyxia at birth. Unless certain clear-cut symptoms are present then, brain abnormalities are probably not the result of a complication during labor or delivery, the new report states.
Rather, there may be other reasons for neonatal encephalopathy, as brain disorders in full-term newborns are called. These include genetic factors and maternal health problems like hypothyroidism, placental abnormalities, major bleeding during pregnancy, infection of the fetal membranes and a stroke in the baby around the time of birth.
"We know that neonatal encephalopathy has a variety of causes, and we hope this report will enable us to provide more accurate information to affected families and devise better methods of prevention and treatment," said Dr. Mary E. D'Alton, chief of maternal-fetal medicine at Columbia University Medical Center, who was chairwoman of the task force.
Neonatal encephalopathy is a syndrome of disturbed neurological function that occurs in full-term baby's first days. It is characterized by impaired consciousness or seizures, often accompanied by breathing difficulties and poor muscle tone and reflexes.
To determine whether an insufficient supply of oxygen and blood during labor and delivery is the likely cause, several factors should be considered together. These include a low Apgar score at 5 and 10 minutes after birth; high acid level (called acidemia) in the umbilical artery; major organ failure; and an M.R.I. scan showing a particular pattern of cerebral injury, according to the new report.
The more of these conditions that are present, the more likely that insufficient oxygen during the birth was responsible for the injury.
Reassuringly, the report pointed out that most infants with low Apgar scores will not develop cerebral palsy. "Even in the presence of significant acidemia, most newborns will be neurologically normal," the committee said. (A doctor evaluates a newborn on five criteria to arrive at the Apgar score, a fast way to gauge the baby's well-being.)
The experts noted that "there are multiple potential causal pathways that lead to cerebral palsy in term infants, and the signs and symptoms of neonatal encephalopathy may range from mild to severe, depending on the nature and timing of the brain injury."
For example, the injury might occur as a result of risk factors at the time of conception or from conditions that develop during pregnancy, like fetal growth retardation or placental lesions.
At this time, there are few effective remedies for those problems, but if certain abnormalities in the fetal heart rate are present when a woman goes into labor, the doctor may be able to prevent a serious brain injury by doing a cesarean delivery.
A major advance during the last decade has been the use of hypothermia for newborn babies who suffer oxygen deficiency. The treatment cools the baby from a body temperature of 98.6 degrees to 92.3 degrees for 72 hours to minimize brain damage. Still, more than 40 percent of babies so treated develop injuries anyway.
Another major advance involves M.R.I. of the baby's brain, which helps to pinpoint both the timing and extent of an injury. If an M.R.I. is abnormal the day the baby is born, Dr. D'Alton said, the injury most likely occurred before delivery.
An abnormal M.R.I. on Day 3, accompanied by certain labor and delivery problems, suggests that oxygen deprivation around the time of birth caused the brain injury. But if the M.R.I. is normal on Day 3 and no oxygen problem occurred during labor and delivery, then oxygen deprivation at birth is an unlikely cause of neonatal encephalopathy, Dr. D'Alton said.
An M.R.I. done 10 days after birth can indicate the extent of a baby's brain injury, Dr. D'Alton said. Brain injuries evolve, and it may take more than a week before the extent is evident on an M.R.I.
"Every major obstetrical facility should consider having an M.R.I. available in the neonatal intensive care unit so that sick babies don't have to be transported elsewhere," Dr. D'Alton added.
Further advances in preventing brain injuries depend largely on "changing the culture of health care delivery from one that names and blames to one that is dedicated to reducing medical errors through a constructive, nonthreatening and professional process," the report said.
In other words, doctors must be more forthcoming in reporting problems encountered during the care of pregnant women, especially at the time of labor and delivery. Such honesty can identify preventable causes of brain injuries in newborns and enable corrective action.
But it would be helpful, too, for families to reconsider a leap to legal action whenever babies are born with a brain injury. Such suits put doctors on the defensive and make them unwilling to report problems that might have been prevented.
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