Written by Alexander Pralea '24
Edited by Angelina Cho '24
In 2014, Apple and Facebook made headlines by announcing that health coverage for female employees would from then on come with a perk: mature oocyte cryopreservation, more commonly referred to as egg freezing and storage . Many critics lauded this move, arguing that the companies’ support of egg freezing better enabled women to take control of their fertility at their own pace. This landmark policy, however, has raised its own questions, namely whether sky-high expectations regarding elective egg freezing have exceeded the still evolving scientific evidence.
In the 20th century, advances in cell biology first unleashed cryopreservation–the cooling of cells and tissues to halt activity and preserve them–to broader applications in clinical medicine . In the blossoming field of reproductive endocrinology and infertility, a subspecialty of obstetrics and gynecology, the effects were revolutionary. By the 1970’s, hundreds of children had been born from frozen sperm, while by 1984, the first child had been born from a frozen embryo created via in-vitro fertilization (IVF)  .
Since that first baby was born from a frozen embryo, technological advancements have improved the efficiency of cryopreservation. In comparative effectiveness studies, vitrification, which speeds up the cooling process to prevent damaging intracellular ice crystals from forming, was more effective relative to the standard treatment of slow freezing . In tandem with modifications to temperature, timing, and the composition of cryoprotectants (the chemicals that prevent cell damage upon freezing), the introduction of vitrification has increased oocyte survival and the proportion of pregnancies carried to term dramatically. Based on this research, the American Society for Reproductive Medicine (ASRM), collaborating with the Society for Assisted Reproductive Technology (SART), announced in 2012 that oocyte cryopreservation was no longer “experimental.”
Beyond just existing studies, ASRM and SART referred to a literature review they conducted analyzing all four of the randomized control trials (RCTs) that had been done up to that point that had compared cryopreserved versus fresh oocytes. According to the literature review, cryopreserving does not affect oocyte survival, fertilization rate, or implantation rate. However, ASRM and SART were quick to qualify their decision to liberalize oocyte cryopreservation recommendations with a series of nuances, which were nonetheless lost in the subsequent media frenzy. They admitted the prevalence of publication bias–only RCTs yielding positive results for cryopreservation were likely to be published–and the potential lack of generalizability because most of the oocytes came from women younger than 30. In fact, they pointed out an Italian study mentioning that for women older than 38, outcomes significantly deteriorate. The final decision emphasized that oocyte cryopreservation should not be used “for the sole purpose of circumventing reproductive aging in healthy women,” or social egg freezing, which is different from medical egg freezing that preserves fertility for cancer patients, among other uses.
Clearly, this last point was lost on many, following the onslaught of sensational media coverage. A notable Bloomberg piece posited that by freezing their eggs, women could “free” their careers , while an Atlantic piece recommended that women freeze their eggs by age 35 to compensate for the existing work culture .
Part of the problem is the public’s lack of scientific knowledge regarding fertility. A 2017 study from Australia surveying university students about their knowledge about the relationship between fertility and age found greater than 75% underestimated the effect of maternal age on fertility, while greater than 95% underestimated the effect of paternal age on fertility. Clearly, early interventions during secondary school education could alleviate some of the strain that many face in their thirties and forties as they try to conceive at a later age. Discussing the merits of egg freezing, especially as the technology evolves, would likely be helpful if done that early.
It is important to emphasize that for many women, egg freezing offers a solution that they may find appealing as they decide to get pregnant. Nonetheless, it is clear that it is no perfect panacea to everyone’s fertility woes; with rates of success that an individual oocyte will yield a pregnancy in the single digits, patients should be counseled about the pros and cons and make a decision with complete knowledge. In the current system, it is clear that many women enter with high hopes, only to be dashed as they realize the reality is less auspicious than they had thought.
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