No link between infertility, rare infant cancer

Children conceived with the help of infertility treatment are no more likely than those conceived naturally to develop infant leukemia, according to the largest study to date to investigate the relationship.

Infant leukemia strikes children before they reach age one, and is believed to be a different disease from leukemias occurring in older children, Dr. Logan G. Spector of the University of Minnesota in Minneapolis, who helped conduct the study, told Reuters Health. The disease is also extremely rare, he added, with about 150 cases being diagnosed in the United States every year. "It's literally less common than the proverbial lightning strike," he said.

"Obviously when you have a disease as rare as this it's very difficult to make progress on finding the causes," he added.

An earlier study had hinted that infertility treatment might be associated with the disease. To investigate further, Spector and his colleagues looked at 443 children with the disease and 324 healthy controls. All of the children had been diagnosed between 1996 and 2006.

The researchers found no association between infertility in parents or infertility treatment and risk of infant leukemia. While they did find that the risk was actually increased for children born to women who weren't trying to get pregnant versus women who'd been trying for less than a year, this finding should be taken with a grain of salt, Spector noted. "The more ways you cut the data, the more likely you are to find something spurious."

Based on the findings, he and his colleagues conclude, "we can potentially rule out large increases in risk associated with parental infertility or its treatment."

The issue of whether infertility and infertility treatment are related to childhood cancers overall remains open, Spector said. He and his colleagues are planning a study to investigate the relationship.

However, he added, "no matter whether a child was born after spontaneous conception or with assistance, the vast majority of those kids are perfectly healthy."

SOURCE: Human Reproduction, online April 10, 2010.