Compared with kids born to subfertile mothers who did not use ART, those conceived via ART methods — such as in vitro fertilization (IVF) — did not have a higher risk of cancer (HR 0.98, 95% CI 0.79-1.22), reported Mandy Spaan, PhD, of Amsterdam University Medical Center and The Netherlands Cancer Institute.
As shown in her presentation at the European Society of Human Reproduction and Embryology annual meeting, the risk of cancer was slightly elevated in kids whose mothers had an intracytoplasmic sperm injection (ICSI) or a frozen embryo transfer, but the increase was not significant.
Additionally, she and her colleagues concluded that kids conceived via ART did not have a higher risk of cancer than those in the general population (standardized incidence ratio 0.98, 95% CI 0.81-1.11).
In a press release, Spaan called the results “quite reassuring, especially for children conceived by IVF,” adding that the findings add important knowledge about the health risks of ART for offspring.
There is growing evidence that IVF may disturb genetic modifications in an embryo prior to implantation, Spaan explained, noting that fertility medications, embryo thawing and freezing, and the medium in which embryos are grown may all have an impact, although further research is necessary.
She said the findings may assist clinicians in communicating information about offspring health risks to couples seeking fertility treatment, providing them with “evidence-based information about the association between ART and cancer risk in children and adolescents.”
The researchers analyzed data from the OMEGA cohort, a nationwide study with prospective follow-up based in The Netherlands. The study included babies born from 1983 to 2012 to women treated at one of 13 IVF clinics or two regional fertility centers.
The team obtained data about fertility treatments and maternal health risks from medical records, the Dutch Perinatal registry, and maternal questionnaires, with information about cancer incidence from The Netherlands Cancer Registry.
Of more than 98,000 live births, about 53,000 were conceived using ART. Overall, 382 cancers were observed — 166 in the ART group, and 222 in the non-ART group. The median age at the end of follow-up was 17 years, but was shorter in the ART-conceived cohort compared with the non-ART group (16 vs 19 years, respectively), the researchers reported.
Kids born to mothers who had ICSI had a numerically higher cancer risk (HR 1.20, 95% CI 0.85-1.70), as did those whose mothers received a frozen embryo transfer (HR 1.25, 95% CI 0.68-2.43), but the findings were not significant. Spaan noted that there were four cases of melanoma in the ICSI children, which may have been due to chance.
There were no increased site-specific risks of cancer in ART babies compared with both the non-ART cohort and the general population. Compared with the non-ART group, ART babies also did not have an increased risk of lymphoblastic leukemia (HR 1.03, 95% CI 0.58-1.82).
After 18 years, the hazard ratio of cancer in ART-conceived babies was 1.22 (95% CI 0.86-1.74), she said.
Spaan acknowledged that the incidence of cancer in this population was low, which may have limited findings from subgroup analyses, specifically about associations between site-specific cancers and frozen embryo transfer.