NEW YORK (Reuters Health) – In preterm infants born at a gestational age of 32 weeks or younger, keeping oxygen saturation low in the first few weeks of life and high later on will reduce the risk of severe retinopathy of prematurity (ROP).

That’s according to a systematic review and meta-analysis of 10 relevant studies (involving more than 3,000 preemies) that reported the association between severe ROP in premature infants with high or low target saturation measured by pulse oximetry.

“The results of our meta-analysis suggest that both timing and oxygen saturation level are important for severe ROP risk reduction,” the investigators write in the June issue of Pediatrics.

In a pooled analysis, senior author Dr. Olaf Dammann of Tufts Medical Center, Boston and colleagues found that low oxygen saturation (70%-96%) in the first postnatal weeks was associated with a statistically significant 52% reduced risk of severe ROP (risk ratio, 0.48).

But after 32 weeks of postmenstrual age (PMA), high oxygen saturation (94%-99%) reduced the risk for progression to severe ROP by 46% (risk ratio, 0.54).

“Our results show that before 32 weeks the response to oxygen is different than after 32 weeks,” Dr. Dammann noted in a telephone interview with Reuters Health. The different effects at postnatal time points