IVF health risks pinpointed
Thorough analysis offers both concern and comfort.
Children conceived by in vitro fertilization (IVF) are at greater risk of certain health problems, the first comprehensive analysis of medical data has found. However, the cause remains unknown.
Around 1% of babies born in the United States start off life in the laboratory, and there has been growing concern that IVF might subtly affect aspects of children's health ranging from birth defects to cancer. But so far, the results of studies examining IVF children have been conflicting or incomplete.
Now a panel of experts has systematically analysed all the available medical literature and concluded that there is at least some increased risk from conceiving in a fertility clinic. The panel reported their preliminary results, based on 169 published studies, at the annual meeting of the American Society for Reproductive Medicine in Philadelphia on Tuesday.
Babies born after IVF are at least twice as likely to die at or soon after birth, or to be born prematurely or with a clinically low birth weight, the panel found. Premature and low-birth-weight babies are thought to suffer more health and developmental problems later in life. The evidence also suggested that IVF children are at greater risk of some rare genetic abnormalities.
Johns Hopkins University in Baltimore
In some respects, however, the group's findings are reassuring, says panel head Kathy Hudson of Johns Hopkins University in Baltimore. The evidence does not show any increase in major birth malformations, cancer or psychological development, in contrast to some recent scares. "What we have found should be very comforting," she says.
Panel members say they can't be sure exactly what causes the problems in IVF children. One possibility is that the technique of fertilizing and growing young embryos in the lab somehow disrupts their normal development, resulting in problems later on.
University of California, San Francisco
Hudson says the panel will next come up with a set of recommendations for how to work out the cause of these health problems and, potentially, how to solve them.
For example, larger, longer and more detailed studies of children born through IVF might reveal particular groups of parents who are at greater risk of health problems, and who could be given additional testing or support. Alternatively, detailed laboratory studies might show that problems can be avoided if embryos are nurtured in one growth solution rather than another.
The panel members acknowledge that parents will probably choose to pursue IVF regardless of the study's conclusions, because they are willing to accept the moderate health risks in exchange for the chance to bear children. But "you have to adequately inform patients of what those risks are", Cedars says.