Study linking IVF, ICSI to birth defects under fire: Critics charge that study's methods are flawed. (Said to Double Defect Risk).

A study that showed double the risk of major birth defects among babies conceived through in vitro fertilization and intracytoplasmic sperm injection is being heavily criticized as having major methodologic flaws that undermine its findings.

"This is the only report of an increase in birth defects in IVF and ICSI, and it doesn't fit any other study," said Dr. Jamie Grifo, president of the Society for Reproductive Technology (SART) and director of the division of reproductive endocrinology at New York University, New York.

In a retrospective analysis of 837 infants conceived through in vitro fertilization (IVF), 301 infants conceived through intracytoplasmic sperm injection (ICSI), and 4,000 naturally conceived infants, an Australian and British team found major birth defects in 8.6% of IVF babies, 9% of ICSI babies, and 4.2% of the naturally conceived babies.

Both the IVF and ICSI babies had twice the relative risk for major birth defects diagnosed at 1 year of age, compared with the naturally conceived babies after adjusting for maternal age and parity, sex of the infant, and correlation between siblings, reported Michele Hansen of the University of Western Australia, Perth, and associates (N. Engl. J. Med. 346 [10]:725-30, 2002).

The IVF and ICSI babies were also more likely to have multiple major defects, chromosomal defects, and musculoskeletal defects.

Dr. Grifo said in an interview that the report is misleading and will needlessly alarm patients. "I'm telling my patients not to worry The jury's still out on this issue, and it won't be fully resolved until we have a good, prospective study," he said.

He criticized the study for being both small and retrospective. The control group was also significantly younger, of greater parity, and was more ethnically diverse than the assisted-conception groups.