A rare in-vitro fertilization technique that addresses male infertility is associated with an increased risk of autism and mental disability in children, compared with standard methods, according to a study that may prompt parents and doctors to take steps to reduce the danger.
The increased risk was among children born as a result of intra-cytoplasmic sperm injection in which a sperm surgically extracted from the testes is injected directly into an egg before being transplanted to the womb. Using the injection method with ejaculated sperm also raised the risks, though not as much, the researchers found. Less than 2 percent of children with either disorder were conceived using IVF, they said.
About 5 million children worldwide have been born by IVF since 1978, and 1.4 percent of total births in the U.S. annually and as many as 4.4 percent in western Europe result from the procedure, according to government and industry figures. Across all types of IVF procedures, compared with spontaneous pregnancies, the study found no increase in the risk of autism and a small increase for mental disability linked only to multiple births, such as twins and triplets.
A perhaps more unexpected finding was an increased risk for both autism and mental retardation after treatment of more severe and not very common cases of male infertility compared with other ICSI techniques, said Karl-Goesta Nygren, one of the study authors and associate professor of obstetrics and gynecology at Swedens Karolinska Institute, during a briefing today in London.
Babies born using intra-cytoplasmic sperm injection, or ICSI, with extracted sperm had a 4.6-fold increased risk of autism, and more than twice the risk of mental disability, compared with more common IVF methods, according to the study. Deploying the technique using ejaculated sperm had a risk of autism that was 1.2 times higher, and a risk of mental disability about 1.47 times higher, compared with standard IVF procedures.
The findings, mined from data in the Swedish national health registers, were published today in the Journal of the American Medical Association.
Factors such as the age of the patients, their psychiatric history, hormone treatments and duration of infertility couldnt explain the result, Nygren said.
The concern about ICSI is whether the risk is associated with the procedure or the indication for the procedure -- male-factor infertility, Marcelle Cedars, professor and director of the University of California, San Franciscos Womens Health Clinical Research Center, said in an editorial accompanying the article. Continued studies and ongoing surveillance are required.
The risk of autism from ICSI using surgically extracted sperm wasnt statistically significant when the analysis excluded twins and triplets. That suggests the risk can be lowered by transferring only one embryo to the womb instead of two or three, said Abraham Reichenberg, another study author at the Institute of Psychiatry at Kings College London.
About 3 percent of women who had IVF treatment in Sweden between 2003 and 2007 used ICSI with surgically extracted sperm, the authors said. The rate is likely to be similarly low in the U.S. and other western European countries, Reichenberg said.
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Rare In-Vitro Technique Raises Autism Risk, Study Says