Children who were conceived with in vitro fertilization have the same overall risk of developing childhood cancers as those conceived naturally, according to the results of a study published in the New England Journal of Medicine.
The use of “assisted conception”—or in vitro fertilization (IVF)—is on the rise, but until now we haven’t known if the process carries inherent risks, such as an increased risk of childhood cancer. More than 5 million children have been conceived with IVF—and some studies have found changes in genes in IVF embryos. The only way to measure whether there is an increased risk of cancer among this population is with accurate population-based data—which is finally starting to accrue.
Researchers from the UK tracked more than 100,000 children conceived by IVF between 1992 and 2008. They analyzed cancer rates among the population and compared them to cancer rates among the general population of children in the UK. They found no increase in the overall risk of cancer among children who were conceived with IVF compared to those who were conceived naturally.
The large sample size allowed the researchers to analyze risk rates for specific types of cancer. When they did this, they found no increased risk of leukemia, neuroblastoma, retinoblastoma, central nervous system tumors, or renal or germ-cell tumors. They did, however, find a small increased risk of two rare cancers: hepatoblastoma (a type of liver cancer) and rhabdomyosarcoma (a muscle cancer). The researchers note that they can’t draw large conclusions about this small increased risk because both cancers are quite rare and the absolute risk is very small. About 6 out of every 1 million children conceived by IVF developed hepatoblastoma.
The researchers concluded that there was no increase in the overall risk of cancer among British children conceived with IVF during the 17-year study period. They note that there were increased risks of hepatoblastoma and rhabdomyosarcoma, but the absolute risks were small.
Williams CL, Bunch KJ, Stiller CA, et al. Cancer risk among children born after assisted conception. New England Journal of Medicine. 2013; 369:1819-1827.