---

---

---

---

Science Current Events and Science News RSS Feeds

---

---

Email a Friend Printer Friendly

Tobacco exposure in womb may slow arousal response and help explain increased cot death risk among babies of smokers

December 17, 2002

A slower arousal response, as a result of tobacco exposure in the womb, might explain the increased risk of cot death (SIDS) among babies of smokers, suggests research in the Archives of Disease in Childhood.

Researchers monitored the sleep and arousal patterns of 20 babies between the ages of 8 and 12 weeks, which is when sudden infant (cot) deaths peak. Half the babies’ mothers smoked during pregnancy; the other half were non-smokers. All of the babies had been born at term and none was sick or had been receiving any treatment.

An aural stimulation test was applied to both ears during rapid eye movement (REM) and non-REM sleep patterns, to test the arousal response over a period of 10 to 12 hours of sleep. The test measures whether there are physiological and behavioural changes, including eye opening and movement, which sustain access to air and protect against life threatening oxygen shortage.

Detailed information was also obtained on feeding practices, the smoking habits of both parents, income and employment status, and levels of postnatal depression - factors known to affect the risk of cot death.

There were no differences in overall sleep patterns, nor arousal from REM sleep among the two sets of babies. But five of the babies whose mothers smoked during the pregnancy did not open their eyes or begin to move after the maximal aural stimulus was applied during non-REM sleep.

Previous research has indicated that cigarette smoking by the mother could be implicated in up to 30% of cases of cot death. And the authors conclude that their findings may partly explain the association between smoking and the risk of SIDS.

British Medical Journal (BMJ)