Toddlers who have obstructed nighttime breathing, or sleep apnea, appear to experience more breathing problems when they sleep on their backs compared to when they sleep in other positions, a new study finds.

The findings, which contradict earlier research, appear in the November issue of the journal Archives of Otolaryngology – Head and Neck Surgery.

Researchers studied the association between obstructive sleep apnea syndrome and body positions by observing 60 toddlers while they slept. They analyzed data about the time spent in each body position during sleep, the number of apnea episodes in each position, blood oxygen levels, time spent in each stage of sleep, and the “respiratory disturbance index (RDI)”.

“The mean RDI rose when more than 50 percent of the time was spent in supine (face forward) sleep,” study lead author Dr. Kevin D. Pereira, a professor of otolaryngology at the University of Texas Medical School in Houston, said in a prepared statement. “There was even more of an increase when supine sleep compromised 75 percent of the total sleep time. In fact, the RDI in this position was greater than in all other positions combined.”

“This finding is in contrast to previous studies that have demonstrated no correlation between sleep position and obstructive sleep apnea in children,” Pereira said.

He noted that this study did not look at infants, so the findings shouldn’t be confused with the healthy practice of having infants sleep on their sides or backs to help avoid Sudden Infant Death Syndrome (SIDS).