However, overall cancer risk was not higher after fertility treatments vs natural conception
While overall cancer risk was no different for children born after fertility treatments compared with those naturally conceived, frozen or fresh embryo transfer did appear to increase risk of leukemia, according to a French cohort study. Among more than 8.5 million children, the overall risk of cancer did not differ between those conceived naturally and those born after fresh embryo transfer (HR 1.12, 95% CI 0.96-1.31), frozen embryo transfer (HR 1.02, 95% CI 0.78-1.32), or artificial insemination (HR 1.09, 95% CI 0.86-1.38), reported Paula Rios, MD, PhD, of the French National Agency for Medicines and Health Products Safety in Saint-Denis, France, and colleagues. However, the risk of acute lymphoblastic leukemia (ALL) was higher among children born after frozen embryo transfer (HR 1.61, 95% CI 1.04-2.50), for a risk difference of 23.2 per million person-years compared with children conceived naturally, they wrote in JAMA Network Open. In addition, among children born from 2010 to 2015, the risk of leukemia was higher among those born after fresh embryo transfer (HR 1.42, 95% CI 1.06-1.92), for an adjusted risk difference of 19.7 per million person-years. "This risk, although resulting in a limited number of cases, needs to be monitored in view of the continuous increase in the use of ART [assisted reproductive technologies]," Rios and colleagues wrote. Among previous studies with 100,000 or more ART-exposed children, there was no increase in overall cancer risk observed, with the exception of one study that reported a "marginal association" with ART. However, positive associations have been documented across studies of specific cancer types, Rios and colleagues said, though these studies "were based on limited numbers of case patients exposed to each ART modality." In an invited commentary, Marie Hargreave, PhD, of the Danish Cancer Institute in Copenhagen, noted that "use of ART has been…