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Tobacco smoking increase the risk of SIDS in infants

Published on March 7th, 2008 15:03

In a study researchers showed the relationship between women who smoke while pregnant and SIDS risk to their babies. SIDS is a sudden infant death syndrome and in USA it is the leading cause of death for babies between 1 month and 1 year old.

SIDS is also known as crib death because it happens most often during sleep, usually between the hours of 10 p.m. and 10 a.m.

Some experts believe that SIDS happens when a baby with an underlying abnormality (for example, a brain defect that affects breathing) sleeps tummy-down or is faced with an environmental challenge such as secondhand smoke during a critical period of growth.

Researchers at McMaster University explained why pregnant women should not smoke, and why SIDS has increased.

"While cigarette smoke contains many different compounds, we found there is a direct impact of one component, nicotine, on the ability of certain cells to detect and respond to oxygen deprivation," says Josef Buttigieg, lead author and a PhD (Doctor of Philosophy) graduate student in the department of Biology. "When a baby is lying face down in bed, for example, it should sense a reduction in oxygen and move its head. But this arousal mechanism doesn't work as it should in babies exposed to nicotine during pregnancy."

Researcher discovered in babies’ body a group of hormones, released by the adrenal glands, named catecholamines. The catecholamines have a big role for babies, they signal the baby's lungs to reabsorb fluid, to take its first breath, and help the heart to beat more efficiently.

“These kinds of hormones appear in babies’ body during birth when the baby is exposed to low oxygen”, explains Buttigieg.

Catecholamines can be impaired only due to nicotine exposure.

"At birth, the nervous control of the adrenal gland is not active and so a baby relies on these direct oxygen sensing mechanisms to release catecholamines," says Colin Nurse, academic advisor on the study and a professor in the department of Biology. "But nicotine causes premature loss of these mechanisms, which would normally occur later in development after nervous control is established. Thus, the infants become much tender to SIDS."

Researchers at McMaster University gave to pregnant women an advice: “Do not smoke, use cocaine, or use heroin. Tobacco, cocaine, or heroin use during pregnancy increases the infant's risk for SIDS.”