Recent research suggests that using in vitro fertilization (IVF) to facilitate pregnancy may increase the newborn’s susceptibility to Beckwith-Wiedemann syndrome (BWS), a rare developmental disorder.

Scientists from the Washington University School of Medicine and the Johns Hopkins University School of Medicine concluded that conception with IVF is six times as common among children with BWS as in the general population. This result expands the small but growing body of evidence that links IVF and birth defects.

IVF is a widely accepted and highly prevalent reproductive alternative for couples who, for biological reasons, cannot conceive a child of their own. Eggs are inseminated and fertilized in a laboratory, and later implanted in the mother’s uterus.

BWS is a rare disorder, with the cause believed to be genetic. Infants born with BWS suffer from overgrowth of various tissues and inherit an inflated risk of tumors and early-childhood cancer.

Michael DeBaun, an assistant professor of pediatrics at the School of Medicine and a physician at St. Louis Children’s Hospital, was the principle investigator involved with the BWS/IVF study.

“At this point, we simply have a strong association between BWS and IVF,” said DeBaun.

DeBaun and his colleagues from Johns Hopkins emphasized that the clinical applications for their findings are still vague. Their research is quite compelling, but still preliminary, and should serve only to stimulate this new area of medical research, not to influence anyone’s decisions concerning reproduction.

“We need additional data to verify our findings, and, if confirmed, to understand why there is an association,” said DeBaun.

Currently, less than one percent of babies born in the United States are conceived via reproductive-assisted technologies. However, in DeBaun’s registry of BWS cases, about five percent of the affected children had IVF births. Moreover, DeBaun feels this percentage could be an underestimate for the population at large.

Despite DeBaun’s results, the Society for Assisted Reproductive Technology remains incredulous, and is not convinced that IVF results in an increased incidence of birth defects. Their stance is supported by similar studies conducted on separate samples, which found no association between IVF and an increased incidence of deformities. They encourage couples not to let these initial investigations impact their reproductive decisions.

For many would-be parents, the slightly increased chance of birth defects might not be an influential argument when they are faced with the option of having a child or not having a child.

Yosuke Miyashita, a former Washington University student who is now a resident in the pediatrics department at Barnes-Jewish Hospital, cares for babies with birth defects and other disorders.

“Since I deal with birth defects on a regular basis,” said Miyashita. “I think it would be tough for me to choose the IVF option, assuming there was a real association with birth defects. Even if the risk was slight, and even if it was my only option.”

There are other explanations for the association. Other scientists offer a possible caveat to DeBaun’s conclusions: The relationship between IVF and BWS could, in reality, be due to a given couple’s infertility abnormalities, rather than being solely attributable to IVF.

Scientists also consider the possibility that the association could be due to age differences. Fertility patients tend to be older, on average, than parents using traditional pregnancy, which may place them in a higher risk category for birth defects.

Investigations of BWS genetics are focusing on a phenomenon called “imprinting”, in which only one of the genes inherited from a parent is functional, while the other is inactivated. Upon examining the DNA of his BWS patients, DeBaun has found “imprinting mutations,” which provides some biological data that strengthens his statistical association.

Over one million children worldwide have been born using assisted reproduction technologies like IVF.

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