Egg Quality Explained

If there's one phrase that can strike fear into any woman going through IVF, it's this one: it might be an egg quality issue.

You hear it in forums, whispered in clinic corridors, mentioned when embryos don't progress, and suddenly it feels like the blame is landing squarely on your shoulders. But here's what nobody tells you clearly: egg quality is not a failure, and it's not something you caused. It's a mix of biology, age, genetics, and randomness.

What egg quality actually means

Every egg has a job: to divide, mature, fertilise, and form a healthy embryo with the right number of chromosomes. A high-quality egg does this smoothly. A poor-quality egg struggles with one of those steps.

Egg quality is not about how healthy you look, how fit you are, how cleanly you eat, how well you've taken care of yourself, whether you're a good person, or whether you're doing IVF right.

If I think about myself and my twin sister, she was the one who smoked and didn't have a great diet growing up, while I was healthy. Yet she got pregnant on her first try, and I was still going six years later. You can be the healthiest person in the world, and it still doesn't guarantee great egg quality.

And to make things more confusing still: you can't see egg quality on a scan. Follicles look identical from the outside. Quality only reveals itself during fertilisation and embryo development, and later through PGT-A testing (which we'll cover separately).

Why egg quality declines with age

Women are born with all the eggs they'll ever have. From birth to puberty the number drops naturally, and through your twenties and thirties the decline continues quietly every cycle. After thirty-five the pace speeds up, and after forty it accelerates again.

This isn't something you caused, and it isn't something you can stop, it's simply how human biology works. Eggs age because the DNA inside them becomes more fragile over time, they age right along with the rest of us.

Older eggs are more likely to:

• Divide incorrectly

• Have the wrong number of chromosomes

• Fail to fertilise

• Stop growing partway through

This is why miscarriage becomes more common as we get older, chromosome formation simply gets more hit-and-miss with age. It's cruel, but it's natural.

Egg quality is not the same as egg quantity

This bit really matters. AMH and AFC tell you how many eggs you may have, that's quantity. They tell you nothing at all about quality.

You can have:

• Low AMH and beautiful eggs

• High AMH and poor-quality eggs (common with PCOS)

• Lots of follicles and few viable embryos

• Few follicles and one perfect embryo

Egg quality and IVF: why it matters so much

In IVF, every step gets magnified. You get to see what normally happens quietly inside the body, and it can be confronting. You might start with ten follicles, collect eight eggs, get five mature, have three fertilise, watch two grow to day three, and end with one blastocyst.

This is something you have to accept doing IVF: nature always narrows the field, IVF just lets you actually watch it happen. When embryos stop growing, it's usually because the egg, or the sperm, didn't have the right structure to continue.

What influences egg quality

Here's what we know can influence egg quality over time:

• Age (by far the biggest factor)

• Genetics

• Oxidative stress

• Hormonal imbalance

• Thyroid function

• Vitamin deficiencies, especially D

• Chronic inflammation

• Severe stress over long periods

• Sleep deprivation

• Metabolic issues like insulin resistance

And also, plain unpredictability. A younger woman can have poor-quality eggs. An older woman can have surprisingly strong ones. You genuinely cannot judge your egg quality from your age, your lifestyle, or your blood tests alone, it only becomes clear once you're actually in an IVF cycle.

What can improve egg quality, and what can't

No supplement, diet or lifestyle change can turn a genetically abnormal egg into a genetically normal one. But you can influence the environment your eggs grow in. Eggs begin maturing around ninety days before ovulation, which means the three months before your cycle genuinely matter.

What helps:

• CoQ10 (especially ubiquinol)

• Omega-3

• Vitamin D

• Balanced blood sugar

• Anti-inflammatory eating (Mediterranean or similar)

• Good sleep

• Moderate exercise

• Reduced alcohol

• Lower chronic stress

• Less exposure to toxins

• Thyroid support if needed

There are other supplements worth considering too, covered in a separate article. None of this guarantees perfect eggs, but it does create the best possible environment for them to develop.

What doesn't help: extreme diets, overtraining, stressing over every tiny decision, or doing everything perfectly to the point of misery.

Sperm quality matters just as much

Eggs tend to get all the blame, but sperm quality influences embryo development too, sometimes even more than people realise. A weak embryo is rarely one-sided, it's usually a combination of egg and sperm factors, or simply nature being selective. This is not your fault.

The emotional impact

This is the part women feel most and talk about least. Being told you have poor egg quality can feel like a punch in the face, honestly. It feels deeply personal, even though it isn't.

You may feel older than your age, betrayed by your own body, jealous, angry, ashamed, or quick to blame yourself. Poor egg quality does not mean you won't be a mother. Many women with challenging egg quality succeed after several cycles. Some succeed with donor eggs. Some succeed naturally later. Some find an entirely different path to the family they always wanted.