The risk for IVF babies was 6.2 percent compared to 4.4 percent for naturally conceived babies. While the finding suggests a relationship between IVF and slightly more birth defects, it does not prove that the IVF procedure itself is the cause.
However, questions raised by the investigation are important to address because nearly 1 percent of all children born in the United States are conceived through IVF, said Brad Van Voorhis, M.D., the F.K. "Ted" Chapler Professor of Reproductive Endocrinology in the UI Roy J. and Lucille A. Carver College of Medicine and a study author.
"The finding indicates that the vast majority of IVF-conceived babies are not affected by major birth defects," Van Voorhis said. "Most appear to be fine, at least up to age 1, which was our study limit. However, the question remains whether the slight increased risk for IVF babies is caused by the treatment itself, by factors in infertile couples who seek IVF or by some combination of the treatment and these factors."
The team did the study because reports from other countries found a slight increase in the risk of major birth defects in babies conceived after IVF procedures, but no similar study had been done in the United States. The UI investigation results appear in the November 2005 issue of the journal Fertility and Sterility. The issue also includes a Finnish study on assisted reproduction and major birth defects, as well as several other articles and letters on the topic.
The UI study was based on births in Iowa from 1989 to 2002 and used assisted reproduction records from UI Hospitals and Clinics and birth defects records from the Iowa Registry for Congenital and Inherited Diso
Contact: Becky Soglin
University of Iowa