Claire Evans decided to freeze her eggs six years ago, when she was 36. The American had just broken up with her fiance and was worried that her time to have a baby was running out. A friend whose own marriage had just ended suggested the procedure.
She took medications to stimulate her ovaries to overproduce eggs, which were frozen to use later and to have a baby at an age when it would be difficult to become pregnant without medical intervention.
How old a woman is when she freezes her eggs, and how many eggs she freezes, make a significant difference in whether she will have a baby. Most women who tried to become pregnant, this American study found, did not succeed
The procedure of egg freezing is an increasingly popular — but, especially in the United States, expensive — option for women who want to delay childbirth. New research documents some caveats, however: how old a woman is when she freezes her eggs, and how many eggs she freezes, make a significant difference in whether she will have a baby. Most women who tried to become pregnant, the study found, did not succeed, often because they had waited until they were too old to freeze eggs and had not frozen enough of them.
That note of caution comes from data published this summer in a paper in the journal Fertility and Sterility from the clinic where Evans froze her eggs — New York University Langone Fertility Center.
Dr Marcelle Cedars, professor and director of the division of reproductive endocrinology at the University of California, San Francisco, who was not involved in the study, says that although the study involved just a single fertility clinic, “it is a centre that is unique for its long duration of follow-up.”
The data, she says, is “sobering” and “should give women pause”. Cedars, who is also the president of the American Society for Reproductive Medicine, adds that many women “are overly optimistic” about their chances of having a baby when they freeze their eggs. It is not, as many assume, an insurance policy.
“The pregnancy rate is not as good as I think a lot of women think it will be,” she says. “I always tell patients, ‘There’s not a baby in the freezer. There’s a chance to get pregnant.’”
The study, led by Dr Sarah Druckenmiller Cascante, a fellow at NYU Langone, and Dr James Grifo, director of the fertility centre, reported that the average age when women froze eggs was 38.3. On average, they waited four years to thaw and fertilise their eggs.
The overall chance of a live birth from the frozen eggs is 39 per cent. But among women who were younger than 38 when they froze their eggs, the live birth rate is 51 per cent. It rises to 70 per cent if women younger than 38 also thawed 20 or more eggs.
The age of the woman when she used the eggs to try to have a baby did not make a difference — all that mattered was how old a woman was when she froze her eggs and how many she froze
The age of the woman when she used the eggs to try to have a baby did not make a difference — all that mattered was how old a woman was when she froze her eggs and how many she froze.
“The reality is most eggs don’t make good embryos,” Grifo says. “The more eggs you have, the better the chance.”
According to the Society for Assisted Reproductive Technology, the number of healthy women freezing eggs rose to 12,438 in 2020 from 7,193 in 2016. But national data on success rates is pretty much nonexistent, says Dr Timothy Hickman, president of the society and medical director of CCRM Fertility in Houston.
“I commend them for doing the study,” Hickman says of the NYU team.
Dr Alan Penzias, a fertility specialist at Boston IVF Fertility Clinic and Beth Israel Deaconess Medical Center who is chair of the practice committee of the American Society for Reproductive Medicine, says data from his centre is consistent with the NYU study. At his centre, he says, women who froze their eggs had one-third of a chance of having a baby when they thawed them.
“Counselling should be clear that there is no guarantee and that the value of delaying having a child must exceed the benefit of delay,” Penzias says.
That trade-off is an issue with his 29-year-old daughter, Rebecca, Penzias says. Rebecca Penzias — who gave him permission to mention her situation and use her name — wants to freeze her eggs because she is studying for a doctorate and is not ready to have a baby. Having some eggs frozen would give her peace of mind.
Alan Penzias says she did not need to freeze her eggs — she has plenty of years of fertility ahead of her — but he considers her reason for freezing sufficient.
His wife, a bioethicist and Rebecca Penzias’s stepmother, disagrees and says she should finish her degree, then try to get pregnant without frozen eggs.
Rebecca Penzias decided to freeze her eggs, planning to do so in October.
The number of eggs collected varies from woman to woman, and for many the only way to get a sufficient number, to increase the chances of success, is to have more than one cycle
Before choosing to freeze their eggs, women also must be prepared for substantial costs. In the US, each egg-retrieval cycle can cost more than $10,000, or about €10,500, Hickman says. (Healthcare prices in the United States are not a reliable guide to the cost of equivalent procedures in Ireland.) The number of eggs collected varies from woman to woman, and for many the only way to get a sufficient number, to increase the chances of success, is to have more than one cycle.
It costs an additional $5,000 to $7,000 to thaw and fertilise the eggs, grow embryos in the lab for a few days, then implant them in the woman’s uterus. Many women, including Evans, have their embryos tested for chromosomal anomalies. That costs an additional $3,000. And storage of frozen eggs can cost more than $1,000 a year.
Some health-insurance policies cover at least part of the costs. But many do not.
Most women end up never using their frozen eggs after paying for egg retrieval and storage, often because they got pregnant on their own.
Evans, though, is a success story. She was young enough when she froze eggs to have a good chance of success and to be able to have eggs retrieved twice to accumulate 20 that could be frozen.
She married in 2019 — to the same man she had been engaged to. Last year she had her eggs thawed and fertilised in a laboratory with her husband’s sperm. Seven months ago she had a baby girl, Fiona.
But the frozen eggs did not work for Evans’s friend who encouraged her to undergo the procedure. In 2020 she had the 10 or so eggs she’d frozen thawed and fertilised. None developed into viable embryos. — This article originally appeared in The New York Times