Women's Fertility and Aging: Why Do Eggs Age? — Possibility of Correcting "Division Errors" Emerges

Why Does "Egg Aging" Occur? —— A "Part of the Cause" is Emerging at the Molecular Level

"It's harder to get pregnant as you age." This is a fact known both empirically and statistically, but the central mystery of "egg aging" still holds many unsolved puzzles.

The latest topic reported by The Washington Post delves a step further into this mystery. The focus is on the "chromosomal unraveling" that occurs as eggs age over many years.

Unlike sperm, eggs are not something that is "continuously produced during life." Women stockpile oocytes (precursors to eggs) formed during the fetal stage, keeping them "on hold" for years until ovulation. This prolonged waiting period is a challenging condition for maintaining chromosomal stability, a common understanding among researchers.

What Happens During Egg Division: The Key is "Chromosome Pairs Not Unraveling"

For successful pregnancy, it is crucial that the number of chromosomes in the egg at fertilization is correct. Eggs undergo a special division called meiosis, reducing the chromosomes to "half" so they can merge with sperm.

During this process, if chromosomes unravel early or are unevenly distributed, it can lead to "aneuploidy," where the egg has too many or too few chromosomes. This can result in implantation failure, miscarriage, or an increased risk of chromosomal disorders.

When "Guardian Spirit" Shugoshin Decreases, Chromosomal "Fasteners" Weaken

The focus of the recent report was on the protein "shugoshin," which indirectly protects the mechanism (cohesion) that correctly aligns and keeps chromosomes "attached" until division. The name is said to be derived from the Japanese "guardian deity (guardian spirit)."

New research (including those at the pre-peer review stage) suggests that as shugoshin decreases with age, the system holding chromosomes becomes fragile, increasing errors in eggs where division "cannot be redone." The Washington Post article describes an experiment using mRNA to restore shugoshin production, increasing the proportion of eggs where chromosomes did not unravel early from "about half to about three-quarters."

Meanwhile, UK reports mention more "clinically oriented" figures, stating that supplementing shugoshin 1 reduced chromosomal defects (though still at the research/preclinical stage). For example, defects observed without treatment significantly decreased with treatment.

What Could Change in the IVF Field? An Approach Directly Touching "Egg Quality"

IVF (in vitro fertilization) has made significant technical advances. Options have expanded in embryo culture technology, pre- and post-fertilization process management, genetic testing, and cryopreservation. However, interventions that "directly improve the egg side" of "age-related decline in egg quality" have been limited.

UK reports also highlight the reality that IVF success rates plummet with age. For instance, while birth rates per embryo transfer are high for those under 35, they drop significantly in the early to mid-40s.

This gap is a "biological wall" that cannot be bridged by effort or information alone, causing distress for many involved. The expression "the roller coaster of IVF" mentioned in the article resonates for this reason.

However, the Journey from "Seems Effective" to "Usable" is Long: Experts' Cautious Perspective

The more promising the theme, the more carefully it must be read. The expert comments from the Science Media Centre serve as a "cool-headed brake."

The main points of caution are threefold.

1. Information is Still Fragmented: Conference abstracts and press information alone do not sufficiently clarify the aims, methods, and evaluations.

2. Limitations of Sample Size and Age Distribution: The scale of about 100 human eggs, the age range of 22-43, detailed effects by age, and differences in background infertility factors are not clearly visible.

3. Safety is the Biggest Hurdle: What to confirm at the embryonic development stage and what is considered "safe." Evaluating long-term effects is even more challenging.

Another expert on the same page states that "egg quality is the biggest factor, and if it can be improved, it would be a significant advancement," but emphasizes that additional data and clinical trials are essential. The coexistence of hope and caution is the reality in this field.

Additionally, company announcements (press releases) present impactful figures like "47% to 71%" and estimates such as "an additional 1 million babies worldwide annually," but here it is important to maintain distance as promotional estimates and wait for academic reproducibility, peer review, and independent verification.

Another Frontline: Research to "Recreate Aging and Isolate Causes"

Apart from the "shugoshin" route, new methods have emerged to make it easier to study egg aging. A research introduction from Yale University describes a system that can quickly recreate "aging-like chromosomal errors" in mouse eggs, suggesting that multiple factors such as cohesion (REC8, etc.), cytoskeleton, and centromere function contribute to increased errors.

"Not a single cause, but multiple weaknesses collapsing simultaneously" —— this perspective is also important when considering the position of shugoshin research.

"Society Delays, Bodies Can't Keep Up" —— The Urgency Created by the Discrepancy

The reports repeatedly highlight the reality where the biologically most fertile period clashes with modern decision-making in education, career, economy, and partnerships. It is challenging to adjust the "optimal period" for pregnancy and childbirth through individual effort alone.

This is why research that can intervene in egg quality holds the potential to alleviate the suffering of those involved, while also sparking discussions on whether "medical technology should impose adaptation only on women."

Reactions on Social Media: Applause of Hope and a Call for "Caution"

This topic also sparked divided reactions on social media. Notably, there was a "celebratory mood" on LinkedIn, where professionals and researchers tend to gather. Posts from Ovo Labs and its co-founders received comments such as "important milestone," "wonderful achievement," and "good luck towards clinical application," with praise for the research team standing out.

On the other hand, the stronger the excitement on social media, the more likely misunderstandings such as "rejuvenation is confirmed" or "treatment is immediately available" mix in during dissemination. In response, expert comments highlighting "safety, information shortage, and caution against excessive IVF add-ons" serve as important counters. In fact, external experts have clearly pointed out "details are still thin" and "safety evaluations are not visible."

The points seen on social media can be roughly categorized into the following three lines.

• Hope (from the perspective of those involved): "If the burden of repeated egg retrieval and transfer can be reduced" —— the expectation that "it might be achievable with one IVF."

• Caution (from a scientific literacy perspective): "There are still preclinical/unreviewed parts," "safety, reproducibility, and clinical endpoints are necessary."

• Social Debate (from a values and system perspective): "Even if technology advances, what about cost and access disparities?" "Will extending the 'age of childbirth' become new pressure?" (This point itself exists as a general discussion and is easily recalled in this context.)
  
  
  

Conclusion: This is Not a "Panacea," But Understanding "Reasons" Can Lead to the Next Treatment

What this research suggests is the hope that the resignation of "inevitable decline in egg quality due to aging" can be gradually "deconstructed" with molecular-level hypotheses.

If the pathway that the decrease in shugoshin, the "guardian spirit," weakens the chromosomal fasteners is correct, intervention points indeed exist.

However, before entering the IVF field, there are high barriers of safety, efficacy, scope of application, cost-effectiveness, and ethics. To foster hope, it is important not to overhype and to follow the process of data accumulation. It might be the "entrance to a revolution" or "a promising branch." In any case, the fact that science has begun to provide tangible insights into the long-standing challenge of egg aging is big news.