Children born after IVF at increased risk for cancer

Kallen B. Pediatrics. 2010;126:e270-e276.

Children born after in vitro fertilization are at a moderately increased risk for cancer, according to new findings from a follow-up analysis in Sweden.

“This is the first study to demonstrate a statistically significant increase in cancer risk among children who are born after IVF,” the researchers wrote. “This is probably not attributable to the IVF procedure itself, but could be an effect of confounding from unidentified characteristics of women who undergo IVF or could act via the widely known increased risks for neonatal complication.”

Previous data suggest no association between an increased risk for cancer and children conceived via IVF. However, most studies were too small, according to the researchers.

Researchers followed 26,692 children born after IVF between 1982 and 2005 included in the Swedish Cancer Registry. Children who had cancer and were born after IVF were compared with children who were not conceived by IVF.

Researchers identified 53 cancer cases in children born after IVF, of whom 18 had hematologic cancer, 17 had eye or central nervous system tumors, 12 had other solid cancers, and six had Langerhans cells histiocytosis.

After adjusting for birth-year, the overall cancer risk estimate was 1.42 (95% CI, 1.09-1.87) and decreased to 1.34 (95% CI, 1.02-1.76), after excluding infants with Langerhans cells histiocytosis.

Although maternal age, parity, smoking prevalence, sub-fertility, previous miscarriages, BMI and multiple births did not significantly increase the risk for cancer, increased birth weight, premature delivery, respiratory diagnoses and low Apgar score were associated with an increased risk for cancer.

Moreover, of the 49 cases of cancer identified after excluding children whose mother was born outside of Sweden or whose father or mother were non-Swedish, the OR increased to 1.52 (95% CI, 1.15-2.02). Children who were conceived after IVF and received a cancer diagnosis before the age of 3 years had an OR of 1.87 (95% CI, 1.27-2.77). The OR decreased to 1.32 (95% CI, 0.89-1.96) in children diagnosed with cancer aged 3 years or older.

The researchers noted that the individual risk for a child who is born after IVF to develop childhood cancer is low and that further studies, including larger cohorts, are needed.

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