Monday, April 7, 2008

One in four premature babies 'faces risk of autism'

By DANIEL MARTIN - Last updated at 00:03am on 7th April 2008

Risk of autism is greatest for children who are the smallest at birth, say scientistsPremature babies could have as much as a one in four risk of developing autism.

The much higher rate offers one explanation for the increase in children diagnosed with autism in recent years, as early births have become more common. One in 100 Britons - around half a million - are estimated to be autistic. Just 20 years ago, scientists estimated that fewer than one in 1,000 people had the condition. But over the same period, there has been a rise in the number of babies born prematurely and surviving into adulthood.

This is attributed to a combination of medical advances and a trend for more older women, for whom premature babies are more likely, to give birth. Almost one in eight babies are born prematurely every year, according to baby charity Bliss. That equates to 76,000 babies in the UK. The Canadian study involved children who were born between seven and 14 weeks prematurely and weighed 3.3lb (1.5kg) or less at birth.

A behavioural test performed at around 21 months of age found suspected autism in 23 of the 91 children. The study also found that the risk of autism was greatest among those children who were the smallest at birth. Experts say babies born early may suffer mentally because their brain is still forming. Previous studies have linked premature birth and low birth weight with developmental problems, including autism.

But the Canadian study is the first to attempt to quantify the risk of autism. The danger was greatest among those children who were the smallest at birth, and those born to mothers who suffered a prenatal infection or bleeding, said Catherine Limperopoulos, lead researcher of the team from McGill University in Montreal.

"Early autistic behaviours seem to be an under-recognised feature of very low birth-weight infants," she said. "Ongoing follow-up is needed to understand if this initial positive screen is transient or persistent."

The toddlers who tested as being at high risk for autism were also more likely to be male, and their mother was more likely to have experienced haemorrhaging during labour and delivery.
Autism can have relatively mild symptoms or can severely disable a child by interfering with speech and behaviour.

Higher rates in recent years have been attributed to various causes, including improved diagnoses. Other studies have found genetic and environmental links to the condition.
But now there is a growing belief that premature births may also be a factor.

The increasing number of mothers who delay giving birth until their forties has been linked in studies to a serious increase in the number of underweight babies. Most low birth-weight babies are born prematurely - that is, born before 37 weeks' gestation. Britain has the second worst rate for low birth weights in western Europe - second only to Greece. The number of over-45s giving birth has doubled in a decade to 1,117 in 2005. Women over 40 have an 8.5 per cent risk of giving birth to underweight babies, compared with 6 per cent for those in their thirties.
Other studies have shown that premature birth and low birth weight babies are more prone to a low IQ, poor cognitive functioning and learning disabilities. They are also more likely to exhibit behavioural problems at school.

On top of this, medical advances mean more premature babies are surviving. Latest figures show that 39 per cent of babies born at 24 weeks live - well up on previous years.

The Canadian study was published in the journal Pediatrics.

Wednesday, April 2, 2008

Drinking while pregnant risks autism in babies

by Sarah-Kate Templeton, Health Editor

Women who drink alcohol during pregnancy may be putting their babies at risk of developing autism, according to new research.

The consultant psychiatrist who alerted the medical profession to the finding that drinking while pregnant can give babies a condition called foetal alcohol syndrome (FAS) has now found that the consumption of alcohol by expecting mothers can also cause autism.

The research is the first to suggest that autism may be triggered by the child’s mother drinking alcohol during pregnancy.

The findings will heighten concern about the increase in alcohol consumption among women of childbearing age.

More than half of all mothers drink alcohol while pregnant, according to the Department of Health. This week the National Institute for Health and Clinical Excellence will issue a new warning about the dangers.

A recent survey showed 8% of women aged 18 to 24 had consumed at least 35 units of alcohol, the equivalent of about 15 glasses of wine, during the previous week. Binge drinking among young women has resulted in the number of alcohol-related deaths in women aged 35 to 54 doubling between 1991 and 2005.

Earlier this year, the British Medical Association warned that the increase in alcohol consumption by young women will be reflected in a rise in drinking during pregnancy and, subsequently, will put more babies at risk of being damaged by alcohol while in the womb.
Raja Mukherjee, consultant psychiatrist at Surrey Borders Partnership NHS trust, has spent the past 18 months examining children who have been damaged by their mother’s drinking during pregnancy and found that a high proportion of them have autism. The research has been presented at scientific meetings.

Mukherjee, who has presented his findings to medical colleagues, declined to discuss them in detail before their publication in a medical journal but said: “Genetic conditions are by far the most common cause of autism but that is not to say that other things cannot cause it, and prenatal alcohol appears, possibly, to be [a cause].

“Unlike genetic conditions, this is 100% preventable.”

Mukherjee has previously warned against any drinking during pregnancy and believes that even low levels of alcohol may endanger babies.

Drinking during pregnancy can cause foetal alcohol spectrum disorder, the umbrella term for a range of disorders — from minor anomalies such as low birth weight to severe FAS, the symptoms of which include mental retardation and facial abnormalities such as a short nose.

The number of cases of FAS in Britain has increased in recent years. So far the government and medical bodies have given out conflicting messages about how much alcohol it is safe to drink during pregnancy.

Cases rising

One per cent of British children suffer from autism, according to the Office for National Statistics. Some academics argue that the percentage of children suffering from the disorder is increasing but others say that numbers are up because of better diagnosis.

Although the cause of autism is unknown, many doctors believe some people have a genetic predisposition towards it.

Dr Andrew Wakefield linked autism to the vaccine for measles, mumps and rubella, but the research was discredited. It led to a fall in immunisation.