Page last updated at 08:09 GMT, Thursday, 22 April 2010 09:09 UK

Methadone use in pregnancy 'may harm babies' sight'

Most babies of methadone-addicted mothers have withdrawal symptoms

Methadone prescribed to pregnant women may be causing sight problems for their babies, a study in Glasgow has found.

The small-scale study found 95% of the 20 children investigated had poor eyesight, while a quarter also had significant developmental problems.

But the report in the British Journal of Ophthalmology said many of the women were also abusing illicit drugs.

Researchers said they could not be sure if methadone alone was responsible and are carrying out further studies.

Methadone is usually prescribed as a substitute for heroin, and is given to heroin-addicted mothers because it allows them to stabilise their life and reduces the risk of their babies being born underweight or premature.

Most of them had reduced vision, by which we mean it was harder for them to see fine detail than their peers
Dr Ruth Hamilton
Glasgow Royal Hospital for Sick Children

However, most babies born to women who are prescribed the opioid during pregnancy have withdrawal symptoms known as neonatal abstinence syndrome (NAS).

The study, carried out at the city's Royal Hospital for Sick Children, examined the eyesight of 20 children whose mothers had taken methadone during pregnancy.

Dr Ruth Hamilton, who was involved in the research, told BBC Radio Scotland's Good Morning Scotland programme: "Most of them had reduced vision, by which we mean it was harder for them to see fine detail than their peers.

"Other problems included what we call nystagmus which is an involuntary shaking of the eye which, of course, blurs their vision anyway and in many cases was the cause of their reduced vision.

"We also saw some more complex problems related to problems at the brain level rather than problems at the eye level."

Developmental problems

More than half of those babies (55%) had also been exposed to either benzodiazepines such as temazepam or heroin (40%) while in the womb.

All but one of the 20 babies had poor eyesight and seven out of 10 had involuntary eye movement (nystagmus), while vision had not yet developed fully in half of the children.

Twelve of the babies in the study had been treated for NAS, while the other eight had not.

Of the 12, one in three (35%) also had a squint, while a similar proportion (30%) had blurred vision or long or short sightedness problems.

One in four had impaired brain function relating to sight and the same proportion had significant developmental problems, including cerebral palsy.

The researchers said the underlying causes of the visual problems were not clear, but that further studies would be conducted to find out more.

A Scottish government spokesperson said: "Guidance on the management and care of pregnant women is clearly outlined in the 'Drug misuse and dependence: UK guidelines on clinical management'.

"These guidelines state that 'Substitute prescribing can occur at any time in pregnancy and carries a lower risk than continuing illicit use.

"It has the advantage of allowing engagement and therefore identification of health and social needs, as well as offering the opportunity for brief interventions and advice to improve outcomes'."

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