Nicotine's Link to SIDS Uncovered

Nicotine Exposure During Pregnancy Puts Infants at Risk

From the WebMD Archives

Sept. 9, 2002 -- Smoking during pregnancy is the biggest known risk factor that contributes to sudden infant death syndrome (SIDS). Now, for the first time, researchers say they've pinpointed at least one way in which nicotine exposure might contribute to SIDS.

A new study suggests that nicotine exposure during pregnancy interferes with receptors in the brain that control breathing and arousal during sleep. That interference could put babies at risk by making it harder for them to wake up when oxygen levels drop.

Study researcher Jean-Pierre Changeux of the Pasteur Institut in Paris and colleagues compared the effects of nicotine on breathing and arousal in normal and mutant mice that lacked a brain receptor that is targeted by nicotine. They studied how the mice reacted in a normal environment and a low oxygen environment that simulated the brief pauses in breathing that naturally occur during sleep.

They found that nicotine injections hampered the breathing responses of normal mice while sleeping but had no effect on the mutant mice.

Researchers say the findings suggest that the receptors in the brain affected by nicotine are critical in fine-tuning breathing and arousal patterns during sleep. And exposure to nicotine during pregnancy may damage the normal function of these receptors -- putting babies at risk of sudden death during otherwise normally tolerated dips in oxygen levels.

The study appears in the Sept. 9 issue of the Proceedings of the National Academy of Sciences.