Fresh and Frozen Embryo Transfers May Increase Risk of Childhood Leukemia

— However, total cancer threat was not greater after fertility treatments vs natural conception

by
Shannon FirthWashington Correspondent, MedPage Today
May 2, 2024

While total cancer threat was no various for kids born after fertility treatments compared to those naturally developed, frozen or fresh embryo transfer did appear to increase threat of leukemia, according to a French accomplice research study.

Amongst more than 8.5 million kids, the total threat of cancer did not vary in between those developed 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 synthetic 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 associates.

The threat of severe lymphoblastic leukemia (ALL) was greater amongst kids born after frozen embryo transfer (HR 1.61, 95% CI 1.04-2.50), for a danger distinction of 23.2 per million person-years compared with kids developed naturally, they composed in JAMA Network Open

In addition, amongst kids born from 2010 to 2015, the danger of leukemia was greater amongst those born after fresh embryo transfer (HR 1.42, 95% CI 1.06-1.92), for an adjusted danger distinction of 19.7 per million person-years.

“This threat, although leading to a minimal variety of cases, requires to be kept an eye on in view of the constant boost in making use of ART [assisted reproductive technologies],” Rios and coworkers composed.

Amongst previous research studies with 100,000 or more ART-exposed kids, there was no boost in general cancer threat observed, with the exception of one research study that reported a “limited association” with ART. Favorable associations have actually been recorded throughout research studies of particular cancer types, Rios and coworkers stated, though these research studies “were based on restricted numbers of case clients exposed to each ART technique.”

In an welcomed commentaryMarie Hargreave, PhD, of the Danish Cancer Institute in Copenhagen, kept in mind that “usage of ART has actually been related to numerous destructive perinatal results amongst kids, consisting of preterm birth and hereditary malformations; disturbingly, numerous top quality research studies and organized evaluations have actually reported increased cancer danger amongst kids born after fertility treatment.”

A 2019 Danish research study of kids born after frozen embryo transfer by Hargreave and coworkers and a 2020 research study of infants with abnormality born after in vitro fertilization both revealed an increased threat of youth cancers. A Dutch research study revealed that kids developed by means of ART approaches were at no higher threat of cancer compared to those born to subfertile moms who did not utilize ART.

For this research study, Rios and associates utilized information from the French National Mother-Child Register (EPI-MERES) for all kids born alive in France from January 2010 through December 2021.

The research study sample consisted of 8,526,306 kids with a mean age of 6.4 years. About half were kids, 96.4% were singletons, 12.1% were little for gestational age at birth, and 3.1% were born with a hereditary malformation. In all, 3.1% of the kids were born following clinically helped recreation, consisting of 1.6% after fresh embryo transfer, 0.8% after frozen embryo transfer, and 0.7% after synthetic insemination.

An overall of 9,256 case clients with cancer were recognized over an average follow-up of 6.7 years, with 165, 57, and 70 born after fresh embryo transfer, frozen embryo transfer, and synthetic insemination, respectively.

Clients with cancer medical diagnoses were most likely to be born preterm, be big for gestational age, and have actually been identified with hereditary malformations compared to kids without cancer.

Leukemia was the most typical cancer detected, representing 29.4% of overall cases, and ALL represented 79.1% of leukemia cases.

Amongst the clients identified with leukemia, 2,635 were developed naturally, 52 were born after fresh embryo transfer, 23 were born after frozen embryo transfer, and 19 were born after synthetic insemination. Amongst the clients detected with ALL, 2,083 were developed naturally, 39 were born after fresh embryo transfer, 20 were born after frozen embryo transfer, and 16 were born after synthetic insemination.

While the variety of births following fresh embryo transfers decreased starting in 2014, the variety of kids born following frozen embryo transfers grew over the research study duration. The variety of annual births after synthetic insemination was steady over the research study duration, the authors kept in mind.

Hargreave kept in mind that the research study authors “appropriately raised the issue that it is unidentified whether the increased leukemia danger observed in their research study may, in truth, be attributable to aspects connected to the underlying infertility instead of the fertility treatment. Other premium research studies with details on maternal infertility have actually reported increased cancer danger amongst kids born after ART, even when utilizing a recommendation group of kids born to moms with fertility issues who did not utilize ART.”