A little oxygen at birth, more cancer risk later?

Babies given 3 or more minutes of oxygen soon after they’re born may run a slightly increased risk of developing cancer later in childhood, according to researchers. The association is not totally clearcut, however.

In a study published in the Journal of Pediatrics, Dr. Logan G. Spector, of the University of Minnesota, Minneapolis, and colleagues examined the relationship between neonatal oxygen supplementation and childhood cancer. Included were 54,795 children born between 1959 and 1966 and followed to age 8.

Compared with giving no supplemental oxygen, the chances of childhood cancer were reduced by 31 percent when oxygen was given for up to 2 minutes, but increased almost threefold with 3 minutes or more of oxygen supplementation.

However, when the analysis was restricted to cancers diagnosed after age 1 year, the differences in risk were not significant from a statistical standpoint, meaning they could have arisen by chance.

Because the findings do not “unambiguously support an association” between neonatal oxygen supplementation and childhood cancer, the investigators do not recommend changes in treatment guidelines. However, additional studies are indicated.

“Pediatricians have already been debating about the possible toxicity of pure oxygen to the eyes, lungs and brain,” Spector commented to Reuters Health. “As a result, several studies have investigated whether room air is as effective as pure oxygen for resuscitating newborns,” he noted. “This study should be evidence in this debate.”

These latest findings “tip the balance toward using room air, and not 100% oxygen, as the first line of treatment for most (poorly breathing) newborns in the delivery room,” Dr. Nigel Paneth, of Michigan State University, East Lansing, writes in an accompanying editorial.

“Oxygen must be available in the delivery room, and there are some circumstances ... where 100% oxygen should perhaps be first-line treatment,” he states. “But even brief neonatal exposures to pure oxygen should no longer be considered familiar, routine and ordinary.”

SOURCE: Journal of Pediatrics, July 2005.

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