imitations can never compete with real ones. This has yet again been proved with two new studies showing that test-tube babies have more chances of having major health problems than normally conceived ones. While more than 90 per cent of babies conceived through assisted reproductive technology (art) are born healthy, the studies indicate that such children have double the risk of having birth defects and low birth weight (www.washingtonpost.com, March 9, 2002).
In the first study, researchers at the University of Western Australia reviewed birth and birth-defect records of 1,138 babies conceived with the help of art and 4,000 children conceived naturally. They found that by the time the infants were a year old, major birth defects were diagnosed in about nine per cent of art children and four per cent kids conceived naturally.
"Their problems ranged from things that are potentially fatal, such as very complex heart defects, to less serious conditions including very large or disfiguring birthmarks," said Jennifer J Kurinczuk, an epidemiologist working at the University of Leicester in England, the uk .
In the second study, researchers at the Centres for Disease Control and Prevention, usa , compared 42,463 test-tube babies with 3.4 million infants conceived naturally. The cdc researchers found that about 6.5 per cent of the art babies had low birth weight. Overall, art pregnancies accounted for three per cent of the nation's low birth weight and four per cent of its very low birth weight babies in 1997 -- a proportionally large share, but a small one in absolute terms.
Low birth weight increases the risk of a baby suffering from mental retardation by about threefold. Very low birth weight infants have rates of severe retardation and cerebral palsy about 30 times that of normal-weight babies. The findings contradict some previous studies that show little or no hazard to art other than the well-recognised chance of having twins or triplets. Both the studies, however, fail to look at the causes behind the high risk rates. The researchers speculate that the problems might be caused by the women's underlying fertility troubles or by the laboratory procedures themselves.
"The two studies are the best of the lot so far on these controversial issues," said Allen A Mitchell of the Boston University School of Public Health, usa . Mitchell said it's important for couples to be sure they are truly infertile before turning to in-vitro fertilisation. "These risks may be acceptable to couples who would not get pregnant without these treatments," he said. "But they may not be acceptable risks for couples who -- if they waited a little longer -- might get pregnant on their own."
The issues are important because various forms of art have entered medical practice without government-required testing of their safety. "More data is required to be obtained," said Jamie Grifo, director of reproductive endocrinology at the New York University School of Medicine, usa.