Bed Sharing Ups Risk for Hypoxia and Hypercapnia in Infants

Steven Fox

July 16, 2012

July 16, 2012 — Bed-sharing infants experience more oxygen desaturations and episodes of carbon dioxide rebreathing than comparable cot-sleeping infants, according to results from a controlled study carried out in New Zealand.

Although the study, published online July 16 in Pediatrics, also found that children who experienced those changes generally showed appropriate behavioral and physiologic responses, the authors caution that some vulnerable infants might not exhibit such responses, and therefore might be at increased risk for sudden infant death syndrome (SIDS).

"Bed-sharing...has special significance in many cultures and is widely practiced for perceived benefits in parent/infant bonding, encouraging breastfeeding, and reducing maternal sleep disruption and infant stress," write Sally Baddock, PhD, from the Department of Women's and Children Health, University of Otago, Dunedin, New Zealand, and colleagues.

However, the researchers note that a number of factors associated with increased risk for SIDS (including parents being overtired, consuming alcohol or sedative drugs, or sleeping on a couch or with excess bedding) could come into play when infants sleep with their parents.

"In this context, it is important to determine behavioral and environmental factors that affect infant physiology and that could increase the risk of SIDS," they write.

To find out more about how bed-sharing might affect risk for SIDS, these investigators studied a group of infants in their own homes to identify and compare desaturation events and rebreathing episodes.

They recruited 40 bed-sleeping families through local postnatal groups and media advertising and matched them, through the postnatal ward of a local hospital, with families of 40 infants who slept in their own cots.

The 40 bed-sleeping infants regularly slept in the same bed with 1 or both parents at least 5 hours each night. The cot-sleeping infants slept in their cots or bassinets for at least 5 hours each night.

The researchers monitored the infants on 2 consecutive nights. During the first night, they were monitored using a video recorder alone. The second night researchers took physiological readings in addition to the video monitoring. The researchers monitored the electrocardiogram, arterial oxygen saturation, heart rate, and respiratory pattern via chest and abdominal bands, airflow via nasal thermistors, and shin and rectal temperature. An attached catheter sampled levels of carbon dioxide in the microenvironment surrounding the child's face.

Mothers also provided demographic data in questionnaires.

The researchers report that desaturation events were more common in bed-sharing infants (risk ratio, 2.17; 95% confidence interval, 1.75 - 2.69) and that this was associated partly with the warmer microenvironment during bed-sharing.

Nearly three quarters of the desaturations in both groups were preceded by central apnea lasting 5 to 10 seconds. There was no accompanying bradycardia, however, and those events usually occurred during active sleep, the researchers write.

Apnea lasting longer than 15 seconds was rare (3 events among bed-sharing infants; 6 among infants sleeping in cots).

Events of oxygen saturation levels dropping below 80% were also uncommon (3 among bed-sharing infants; 4 among cot-sleeping infants).

The researchers identified 80 episodes of rebreathing. Those occurred among 22 bed-sharing infants, but only 1 who slept in a cot. Nearly all of those events were preceded by head covering.

Even so, the researchers noted that the bed-sharing infants maintained normal oxygenation and were therefore deemed to be at low risk for SIDS. All the infants maintained arterial oxygen saturation levels at the baseline of 97.6% during the rebreathing episodes, they write.

They suggest, however, that the characteristics of the sampled families (relatively few smokers, high standard of maternal education, and high breast-feeding rate) might help explain why the infants seemed to be able to physiologically adapt to their warmer, sometimes stuffier microenvironments in the parental bed. It could be that children being raised in less favorable environments might not be as adaptable, they say.

"The effect of repeated exposure to oxygen desaturation in vulnerable infants is unknown as is the ability of vulnerable infants to respond effectively to rebreathing caused by head covering," the authors conclude.

Funding was obtained from the Health Research Council of New Zealand, a University of Otago Research Grant, and a Fanny Evans Scholarship. The authors have disclosed no relevant financial relationships.

Pediatrics. Published online July 16, 2012. Abstract


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