- The Washington Times - Thursday, February 8, 2007

SAN FRANCISCO (AP) — Babies conceived through fertility treatments have higher rates of birth defects, but the overall risk is so small that it should not keep couples from having children this way, doctors are reporting.

The news comes from a study of more than 61,000 births in Canada, the largest ever done in North America.

“What’s important and reassuring is that the absolute risks are still low,” at less than 3 percent of all births, said one of the study’s leaders, Dr. Mark Walker of the University of Ottawa.

Couples who want to lower the risk should have only one or two embryos implanted at a time, specialists said. The danger of defects from twin, triplet and other multiple births is far greater than any risk posed by the fertility treatments themselves.

Results of the study were to be reported today at a meeting of the Society for Maternal-Fetal Medicine in San Francisco.

Researchers studied 61,208 births in Ontario during 2005, including 1,394 that resulted from fertility treatments. They looked at rates of birth defects and adjusted estimates of risk to reflect differences in the mothers’ ages, whether the mothers smoked, the sex of the babies, birth complications and other factors.

Nearly 3 percent of assisted reproductive technology babies had a birth defect versus just less than 2 percent for babies conceived naturally. That translated to a 58 percent greater risk. The chances of a defect rose as the complexity of reproductive help did — they were highest for in vitro fertilization and lowest for simply giving medications to spur a woman’s ovaries to make more eggs.

The biggest difference was seen in the rate of gastrointestinal problems, such as defects in the abdominal wall or organs not in the right place. Babies conceived through reproductive technology were nearly nine times more likely to have such problems — one in 200 births versus six per 10,000 for the others.



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