Children born after medically assisted reproduction (MAR) are at an increased risk of developing leukemia, according to a recently published study in JAMA Network Open.
Among the more than 8.5 million children with a median age of 6.4 years born in France between 2010 and 2021, the overall risk of cancer was the same among those conceived naturally and those born after fresh embryo transfer (hazard ratio of 1.12), frozen embryo transfer (hazard ratio of 1.02), or artificial insemination (hazard ratio of 1.09). A hazard ratio compares the occurrence of an event between two groups. A hazard ratio of 1 indicates equal event occurrence between treatment and control groups.
Additionally, a secondary analysis of children born from 2010 to 2015 found an increased risk of leukemia among children conceived through frozen embryo transfer—although it was not statistically significant—and fresh embryo transfer.
“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 technology],” Dr. Paula Rios of the French National Agency for Medicines and Health Products Safety and her co-authors wrote.
According to the study, children born after MAR were more likely to be part of multiple births, have lower birth weight and gestational age, and were more often born smaller or diagnosed with a congenital malformation. Children born after frozen embryo transfer were more likely to be larger than those of gestational age and were born to older mothers.
Of the cancers studied, leukemia was the most commonly diagnosed type of cancer, making up 29 percent of total cases, and acute lymphoblastic leukemia accounted for 79 percent of the leukemia cases.
Leukemia is the most commonly diagnosed cancer among children, and acute lymphoblastic leukemia is the most frequently diagnosed type—accounting for up to 80 percent of all cases in the pediatric population.
Excluding leukemia, the most frequently diagnosed cancers observed by researchers were tumors of the central nervous system (CNS), embryonal tumors, and lymphomas, although the risk of these cancers did not differ among children born after fresh or frozen embryonic transfer.
Other Studies Suggest Higher Cancer Risk
According to the paper, the mechanisms behind the potential increased risk of cancer among children born after MAR are unknown, and previous studies have shown conflicting results. Some research suggests epigenetic disturbances caused by MAR may be to blame.However, positive associations have been observed in studies that have examined specific cancer types and in previous studies that have evaluated the risk of childhood cancer associated with fresh or frozen embryonic transfer.
According to Ms. Hargreave’s commentary, ART has been reported following other childhood cancers, including hepatoblastoma, neuroblastoma, retinoblastoma, tumors of the central nervous system, and sarcoma, but studies on these types of cancers are difficult.
“Leukemia is the most common childhood cancer type, and investigating other types is difficult because of their rarity,” she wrote. “Hence, although accumulating evidence seems to indicate an increased risk mainly for leukemia, studies may be statistically underpowered to show associations for the rarer cancer types.”
