Cot Death Causes Breakthough

Breakthrough in battle to beat cot deaths as scientists find link to problems in womb

Scientists have come closer to solving the riddle of cot death with the discovery that more than half of all babies who die unexpectedly may have had problems in the womb.

A study of birth records in Scotland shows that mothers who had a placenta defect were up to three times more likely to have a baby who later suffered cot death.

The finding is a key piece in the cot death puzzle, which has mystified researchers for 30 years. A total of 354 babies died of sudden infant death syndrome (Sids) in 2003 in Britain and it is still the most common cause of death in infants in the industrialised world.

Researchers at Cambridge University and the Department of Public Health at the Greater Glasgow Health Board say the babies may have been deprived of oxygen or nutrients before birth, which affected the development of the brain functions controlling the heart and lungs.

This could put them at greater risk from environmental stresses after birth, such as overheating or cigarette smoke, which are known to increase the likelihood of cot death.

Campaigns during the 1990s to get parents to put their babies to sleep on their backs and to ban smoking from the bedroom helped to cut cot deaths by 70 per cent. But progress in reducing the cot death rate further has since slowed.

The distress caused by the tragedies is exacerbated by the lack of any explanation. It can also arouse suspicions which, in some cases, have led to accusations of murder

If confirmed, the finding, published in the New England Journal of Medicine, could lead to a test that would enable doctors to identify vulnerable babies at birth and help parents to monitor them more closely during their crucial first year.

Previous research has shown that babies who grow poorly in the womb or who have difficult births are at greater risk of cot death, but the nature of the link has remained obscure.

Researchers examined the records of 214,000 women who gave birth in Scotland, of whom 114 suffered cot deaths. All the mothers underwent routine blood tests for Down's syndrome and other abnormalities during the second trimester of pregnancy.

The results showed that there were 7.5 cot deaths per 10,000 births among the mothers with the highest levels of alpha-feto protein in their blood, compared with 2.5 per 10,000 births among those with the lowest levels.

Gordon Smith,from Cambridge University, who led the study, said that in at least half of cot deaths, there is a biological vulnerability that puts the babies at increased risk. This is probably an underestimate and we could say there is a biological determinant for the majority of Sids deaths.

Profesor Smith speaking to the BBC, stressed that, even in the high-risk group, the chances of a cot death were less than one in 1,000, and the finding did not undermine earlier advice to put babies to sleep on their back or avoid exposing them to cigarette smoke. There is no reason for women who have a high alpha-feto protein level,to panic but these babies may be more vulnerable.

The presence of alpha-feto protein, which comes from the foetus, in the mother's blood suggests that the placenta is "leaky" and indicates a defect in placental function. If the baby is not getting the oxygen or nutrients it needs that could affect the development of the control mechanisms in the brain of the heart and respiration. A bad environment in the womb may affect the baby's response to a bad environment after birth were the teams conclusions.

The next stage of the research would be to develop a more accurate test to detect babies at risk of Sids a more predictive indicator which would include gestational age, sex and birth weight,

Source New England Journal of Medicine: bbc: Cambridge University