IN Ireland, most pregnant women will be given at least one ultrasound scan as a matter of routine.
The thing is, if routine scans are the answer, what is the question? While there is some evidence to support selective use of ultrasound in high risk pregnancies, there is none to suggest that routine scanning has any value at all. More worryingly, some studies suggest possible ill effects to mother and baby.
What we don't know about ultrasound scanning far outweighs what we do, Twelve years ago, a Lancet editorial concluded that "the data - on the biological effects of ultrasound - are seriously deficient and many questions have not been addressed".
This is still largely true, according to Pat Thomas, author of Every Woman's Birthrights, except that since then some major studies have given rise to the view that there is no medical reason to support routine scanning.
"In 1993 two important pieces of research were published," she said. "A US study concluded that an ultrasound scan made no difference to the outcome of a pregnancy. And British researchers set out to prove the safety of scanning but found the opposite - that women who are intensively scanned are at greater risk of having babies suffering from growth retardation."
Thomas listed other ill effects suggested by research, a negative effect on neurological function, leading to more babies who are left handed, dyslexic or delayed speakers; inaccurate diagnosis of some conditions, such as placenta praevia, and a doubling of risk of premature labour and miscarriage for some women.
Ultrasound is used mainly to confirm dates but also to detect congenital abnormalities. Unfortunately scans are not always accurate, a fact ignored by most enthusiasts. A number of cases in Britain illustrate what Thomas calls "the hit and miss quality of ultrasound examinations". At one Cardiff hospital several women were diagnosed as having dead babies and recommended a termination, only to find out just before the operation that all was well. A report from Yorkshire revealed the opposite problem - one in 200 foetuses terminated because of abnormalities detected by ultrasound were perfectly formed.
If these are the possible problems, what are the reasons for the routine offering of ultrasound scanning in Irish maternity hospitals? Dr Michael Turner, Master of the Coombe Women's Hospital, said he "was not aware of evidence that ultrasound could be harmful". At the National Maternity Hospital in Holles Street, Liz Cotter, sister in charge of foetal assessment, was familiar with the research and quoted a recent article in the journal Ultrasound in Obstetrics and Gynaecology which reviewed the evidence.
This article concluded that "no associations between ultrasound exposure in utero and childhood maldevelopment have been proven. There are, however, some issues, such as non righthandedness and low birth weight after frequent exposures for which no firm conclusion can yet be drawn." It did not address any of the other concerns.
"In Holles Street we offer one routine scan at around 18 weeks to confirm dates," said Liz Cotter, "but otherwise only if it's medically indicated. We largely offer scans because of demand - we're under pressure from mothers."
Berna O'Hanrahan, of the Association for Improvements in the Maternity Services (AIMS) agreed that "most parents love a picture of junior in utero", but argues that this is an issue of consumer education.
"Few mothers are informed of the issues," according to Pat Thomas. "While hospitals always talk about women being the ones who want scanning, hospitals in Britain where scanning is not routinely offered are finding that fewer mothers choose to have one."
One reason why ultrasound is accepted so uncritically is that it addresses fears about imperfect babies. She believes that antenatal classes could allay these fears with education and reassurance, but instead mothers are urged to put their faith in technology.
"Therapists like technology because it allows them to take charge of a process that will go on fine without them," she said. "The development, use and research into ultrasound has in many ways paralleled that of the X ray. Mothers were routinely subjected to X rays for nearly 50 years, all the while being told that it was perfectly safe, until a flood of research proved it to be causing an increase in childhood cancer."
One way or another there does seem to be a case for questioning the routine use of ultrasound.