Children born from frozen embryos are more likely to develop cancer later in life –

An alarming new study finds that babies born from embryos placed in frozen storage have an increased risk of developing cancer.

Researchers at the University of Gothenburg in Sweden have found that children born from frozen embryos are particularly at risk of developing leukemia and tumors related to the central nervous system. Interestingly, the same risk was not found for babies born with other assisted insemination methods.

Births from frozen embryos are relatively rare, accounting for a small percentage of all children born using assisted reproductive technology (ART), and as a result few large-scale population data are available.

There are currently over a million frozen embryos in the United States, but the vast majority will never be used. Penn Medicine reports that nearly one million babies were born through IVF between 1987 and 2015, although nearly all babies are born with a fresh embryo.

A report from the Centers for Disease Control and Prevention published in 2017 found that there were approximately 29,000 frozen embryos in the United States in 2015 that led to a live birth, the latest data available.

Publishing their results in PLL last week, the researchers collected data from 7.9 million children in four Scandinavian countries: Denmark, Finland, Norway and Sweden.

Of this population, 172,000 were born using some form of ART, and 22,630 were from a frozen embryo.

The researchers found that babies born after the embryo thawed were more likely to develop cancer at a young age, with leukemia and central nervous system tumors usually affecting the brain or spinal cord being the most common.

On average, 2.07 out of 1000 babies born by spontaneous conception developed cancer.

Babies born from a new embryo, which make up the majority of IVF pregnancies, were slightly less likely to develop cancer. The researchers found that 1.97 out of 1,000 people developed the disease.

Those born from a frozen embryo were most at risk, with 2.12 per 1000 diagnosed.

Even babies born from frozen embryos often faced diagnosis at an earlier age. The study found 30.08 cases every 100,000 years; this nearly doubled the number of fresh embryo and spontaneous birth clusters.

However, the overall number of cases was low, and the researchers do not believe this should deter a potential family from freezing their embryos.

“Individual risk was low, but may have an impact due to the large increase in population-level assisted reproduction post-freezing cycles,” said study co-author Ulla-Britt Wennerholm, who served as OBGYN, as noted by the UPIA.

“Overall, babies born after assisted reproductive technology did not have an increase in cancer.”

Researchers aren’t sure why babies born from frozen embryos are more at risk, although they have some theories.

‘The reason for the possible increased risk of cancer in babies born later’ [embryo freezing] unknown,” they wrote.

“Each type of cancer in children has its own risk factor profile, but many forms of childhood cancer are believed to result from embryonic accidents and occur in the womb.

High birth weight has also been associated with a higher risk of childhood cancer. [changes to the DNA based on environment] has been suggested as a possible explanation.

The number of women freezing eggs has exploded in recent years as many in the western world choose to cut down on starting a family to meet their career goals.

In 2018, 13,000 women chose to freeze embryos, which in 2009 had fewer than 500 nearly a decade ago.