What is Egg Quality?
💡 Egg quality = chromosomal integrity (euploidy) and developmental competence. Cannot be measured before fertilisation — inferred from embryo development and PGT-A. Aneuploidy rate: ~25% at 35, ~50% at 40, ~70–80% at 43. Primary driver of age-related IVF failure and miscarriage.
Egg quality refers to the chromosomal normality and developmental competence of an oocyte — its likelihood of being successfully fertilised and developing into a viable embryo. It cannot be measured directly before fertilisation and declines significantly with age, especially after 37.
🇮🇳 India Context: Egg Quality is widely assessed and treated across major Indian fertility centres including Chennai, Mumbai, Bangalore, Delhi, and Hyderabad.
What are the key characteristics of Egg Quality?
- Defined as chromosomal integrity (euploidy) + mitochondrial health + developmental competence of the oocyte
- Cannot be directly measured before fertilisation — inferred from embryo morphology, blastocyst development rate, and PGT-A
- Age-dependent decline: aneuploidy rate ~15–20% at age 30; ~35% at 37; ~50% at 40; ~70–80% at 43+
- Aneuploidy is the leading cause of: failed fertilisation, arrested embryo development, implantation failure, and miscarriage
- Distinct from egg quantity (ovarian reserve): a woman can have many eggs (normal AMH) but poor quality due to age
- A young woman with low egg reserve typically has normal quality eggs — poor reserve ≠ poor quality
- PGT-A: trophectoderm biopsy at Day 5 identifies euploid embryos before transfer — improves per-transfer success in older women
- Donor eggs from younger women carry donor’s egg quality regardless of recipient’s age — explains high donor egg IVF success rates
How does Egg Quality work?
Why does Egg Quality matter in fertility?
Egg quality is the primary biological reason IVF success rates decline with age — not uterine function, which remains relatively preserved until perimenopause. Women using donor eggs achieve 50–60% live birth rates per transfer at any age, directly proving it is egg quality, not the uterus, that limits success. This is the most important concept to explain when counselling women over 40 about IVF versus donor egg pathways. PGT-A testing is now routinely offered in India at major fertility centres for women over 37, those with recurrent IVF failure, and those with recurrent miscarriage — it selects euploid embryos and reduces miscarriage risk by identifying chromosomally normal embryos before transfer.
What are related terms to Egg Quality?
Oocyte
An oocyte is the female reproductive cell — the egg — produced by the ovaries. A…
Ovarian Reserve
Ovarian reserve refers to the quantity and functional potential of remaining ooc…
Blastocyst
A blastocyst is a day 5 to 7 embryo that has developed a fluid-filled central ca…
IVF with Donor Eggs
IVF with Donor Eggs is an assisted reproductive procedure in which eggs from a h…
Low Ovarian Reserve (Diminished Ovarian Reserve)
Low Ovarian Reserve means a woman has fewer eggs than expected for her age. It i…
FAQs about Egg Quality
What determines egg quality?
Egg quality is primarily determined by age — specifically the chromosomal integrity of the oocyte. As women age, meiotic spindle formation becomes error-prone, producing aneuploid eggs (wrong chromosome number). Aneuploidy rate: ~20% at 30, ~35% at 37, ~50% at 40, ~70–80% at 43+. Lifestyle (smoking, obesity) has a modest secondary effect.
How can you improve egg quality?
Age-related aneuploidy cannot be reversed. Modest evidence supports: CoQ10 (600–1,200 mg/day) for mitochondrial support — studied in poor responders; stopping smoking (smoking accelerates oocyte aneuploidy); achieving healthy BMI; reducing oxidative stress. No supplement has proven ability to restore age-appropriate egg quality in women over 40.
Can you tell if egg quality is poor before IVF?
No — egg quality cannot be measured before fertilisation. It is inferred from: poor embryo development rate in previous IVF cycles, high blastocyst aneuploidy on PGT-A, repeated implantation failure, and age. A woman’s age is the most reliable proxy for egg quality — the older the egg source, the higher the expected aneuploidy rate.
What is the difference between egg quality and egg reserve?
Egg reserve (quantity): how many eggs remain — measured by AMH and AFC. Egg quality (chromosomal integrity): whether eggs are chromosomally normal — determined primarily by age. These are independent: a 43-year-old may have normal AMH (adequate quantity) but ~75% aneuploid eggs (poor quality). A 28-year-old with low AMH has few eggs but they are typically normal quality.
Does donor egg IVF improve outcomes for poor egg quality?
Yes — dramatically. Donor egg IVF uses eggs from a young donor (21–30 years), whose eggs have low aneuploidy rates. Live birth rates: 50–60% per transfer, regardless of recipient’s age. This is the definitive treatment for age-related egg quality decline, repeated IVF failure due to poor embryo development, and premature ovarian insufficiency.
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