Age is one of the most important determinants of female fertility.

Understanding why can help women make informed reproductive choices without creating unnecessary fear.

Women Are Born With Their Eggs

The ovarian egg supply is established before birth.

The number declines continuously throughout life until menopause.

Unlike sperm, eggs are not continually replenished.

Egg Quality Also Changes

The issue is not simply that fewer eggs remain.

As women become older, the proportion of eggs with chromosome abnormalities increases.

This affects:

• Natural conception
• IVF success
• Implantation
• Miscarriage risk

Why 35 Is Not a Fertility Cliff

Fertility does not suddenly disappear on a woman’s 35th birthday.

The decline is gradual.

However, the rate becomes more clinically significant through the later 30s and particularly into the 40s.

Age thresholds are therefore useful for deciding when to investigate infertility, but they should not be interpreted as biological switches.

Can AMH Tell You How Long You Have Left?

No.

AMH is helpful for estimating ovarian reserve and response to fertility medication.

It cannot accurately tell an individual woman how many fertile years she has remaining.

Nor does a normal AMH eliminate age-related changes in egg quality.

Can IVF Reverse Ageing?

IVF can overcome several barriers to conception and can increase the number of eggs available during a treatment attempt.

But IVF cannot make eggs biologically younger.

This is why IVF success rates using a woman’s own eggs decline with advancing age.

Planning Ahead

Women who expect to delay pregnancy may wish to discuss fertility preservation.

Egg freezing is not necessary for everyone, but understanding the relationship between age and fertility allows informed planning.

The Take-Home Message

Female fertility declines because both egg quantity and egg quality change with time.

AMH helps assess quantity; age remains one of the strongest indicators of egg quality.

Understanding the difference is fundamental when considering natural conception, IVF or fertility preservation.