Caroline Helwick

October 20, 2012

October 20, 2012 (New Orleans, Louisiana) — Infants born as a result of assisted reproductive technology (ART) had a higher incidence of birth defects than naturally conceived infants, in an analysis of all births in California between 2006 and 2007.

"California has the highest number of infants born after ART in this country, and we saw this as an opportunity to explore the relationship between ART and birth defects," said Lorraine Kelley-Quon, MD, a general surgery resident at Ronald Reagan UCLA Medical Center, who conducted the research at Mattel Children's Hospital UCLA (University of California in Los Angeles).

Researchers found a 35% increased risk for birth defects among children born after ART over naturally conceived infants.

"For parents considering in vitro fertilization (IVF) or other forms of ART, it is important to understand and discuss with their doctor the potential risks of the procedure before making a decision," Dr. Kelley-Quon advised.

The new results were reported here at the 2012 American Academy of Pediatrics National Conference and Exhibition.

Propensity Matched

Investigators analyzed the state's maternal/infant dataset of 2006 and 2007, identifying infants born after ART (IVF, gamete intrafallopian transfer) and those born after non-IVF fertility-related services (FRS), including fertility-enhancing drugs, artificial insemination, and intrauterine insemination.

These infants were propensity matched to naturally conceived infants according to maternal age, parity, and plurality; race; and infant gender and year of birth.

A bivariate analysis was performed for the ART cohort vs controls and for the FRS cohort vs controls. Multivariate analysis identified factors associated with birth defects.

In the FRS bivariate analysis, 119 of 1749 (9.7%) infants had birth defects compared with 1106 (6.3%) controls, but the difference was not statistically significant (P = .438) in the regression analysis.

For the ART comparison, however, and after adjustments for maternal factors, birth defects were significantly more common among ART infants than among controls. The registry indicated birth defects in 432 of 4795 (9.0%) ART infants compared with 3031 (6.6%) naturally conceived infants (P < .001), Dr. Kelley-Quon reported.

Differences were most notable for several organ systems. Statistically significant differences were seen in malformations of the eye (0.3% vs 0.2%), heart (4.8 % vs 3.0%), and genitourinary system (1.5% vs 1.0%).

Overall, in the regression analysis, the odds of birth defects among ART infants were 35% greater than those for naturally conceived infants with similar maternal characteristics; the greatest odds ratio (2.41) was observed for eye abnormalities.

It is interesting to note that the ART cohort had an 80% reduced risk of having a chromosomal abnormality over controls (0.2% vs 0.5%; P < .001).

"The risks were more pronounced in multiples versus singletons," Dr. Kelley-Quon added. "And the risks of birth defects after other fertility treatments such as artificial insemination or ovulation induction alone were not significant."

Ongoing Concern

Sherif Emil, MD, director of pediatric general surgery at The Montreal Children's Hospital, in Quebec, Canada, who moderated the session, said there has been "ongoing concern" about a possible relationship between ART and birth defects.

"These findings suggest that parents should have a good discussion with the physician who is performing the ART procedure," he said. It is best to examine the statistics specific to the ART center they are using, he added.

Mary Brandt, MD, professor and chair of surgery at Texas Children's Hospital, in Houston, agreed that parents need to be aware of these findings but should understand that "the individual risk for a single family is not this percentage. The actual numbers are still very small — though there are increased odds," she said.

Dr. Brandt added that the study has "fascinating implications in terms of embryology," and that research is needed to determine what factors underlie these differences. "It may not be the result of IVF per se, but [rather of] mechanical issues, parental factors, and so forth," she offered.

Dr. Kelley-Quon, Dr. Emil, and Dr. Brandt have disclosed no relevant financial relationships.

The 2012 American Academy of Pediatrics National Conference and Exhibition: Abstract 17831. Presented October 20, 2012.