THURSDAY, Aug. 5, 2004 (HealthDayNews) -- When all the evidence is weighed, delaying delivery of a premature baby by a few days is better for the infant's health, a new study says.
When the risks of waiting or delivering quickly are balanced, the study says, holding off is likelier to prevent brain damage, particularly if the fetus is less than 30 weeks old.
"The number one problem in obstetrics is the baby that is failing to grow or failing to thrive in the womb," explained study author Dr. Jim Thornton, a professor of obstetrics and gynecology at City Hospital in Nottingham, England.
When this happens, the only available treatment is to deliver the baby. "Until now, the point at which they said the baby is better out than in was based on hunch and intuition," Thornton said. "There was never a randomized controlled trial to choose the right time."
But that hunch had to take into account various factors. Premature delivery carries with it the risk of respiratory distress syndrome, cerebral palsy and other problems. Continuing the pregnancy could result in oxygen deficiency and stillbirth.
The current research, called the Growth Restriction Intervention Trial, was designed to ascertain the effect of early delivery on mortality and brain damage. The results appear in the Aug. 7 issue of The Lancet.
To this end, the study authors recruited 548 pregnant women around Europe with fetal trauma and who were between 24 and 36 weeks' gestation. Forty weeks' gestation is considered normal, 36 weeks is just slightly premature, and 24 weeks is the absolute lowest limit of survival for the infant, Thornton said. "We were trying to weight how sick the baby was along with the prematurity," he added. "We were weighing two continuous variables together."
The women in the study qualified as "borderline" cases, where the doctor was not sure if the delivery should take place immediately or later. Of 588 babies represented, 296 were randomized to immediate delivery and 292 were deferred.
The death rates were about the same in the two groups. "Doctors are right on the button. They are picking the right moment," Thornton said.
However, when brain damage was taken into account, delaying the delivery seemed to be the better choice. "There's a trend towards less brain damage in the delay group. The brain damage is real big stuff. It's cerebral palsy," Thornton said. Although the trend was not technically statistically significant, "it was a big difference clinically," he added.
At age 2, the rate of "disability" (which included cerebral palsy) was 8 percent among children who were born in the immediate group and 4 percent in those whose births were delayed. Most of the difference was seen in babies who were younger than 31 weeks at gestation.
"This has given a clear answer," Thornton said. "Experts will now recalibrate themselves slightly for a little bit longer." That "little bit longer" amounted to an average of four-and-a-half days.
Others, however, are not so sure the results of this trial will translate into immediate action. As with most pregnancies, it may be best to delay a firm conclusion.
Although, in general, the longer a baby stays inside the uterus the better, "there are multiple factors that play a role in the final outcome of the baby," said Dr. Pradeep Mally, attending neonatologist at New York University School of Medicine. It is impossible, therefore, to make sweeping statements about when delivery should take place.
For more on premature babies, visit the Nemours Foundation.