A woman is born with all the eggs she will ever have, and both their number and quality fall over time. Understanding this, and what tests like AMH can and cannot tell you, helps you plan without unnecessary worry.
How age affects your eggs
Eggs are not made throughout life. According to ASRM, the number of eggs falls from about 6 to 7 million before birth to about 1 to 2 million at birth, and keeps falling until menopause.
ASRM explains that a woman is born with all her eggs. No new eggs are made later, so the supply only falls over time.
Quality matters as much as quantity. As women age, more eggs carry chromosome errors. This is one reason miscarriage and chromosome conditions such as Down syndrome become more common with age.
Male age matters too. ASRM notes that sperm changes in men's mid-to-late 40s can affect fertility, though this happens later than in women.
What is ovarian reserve?
Ovarian reserve describes how many eggs remain in the ovaries. Doctors estimate it with a few tests, often used together.
| Test | How it is done |
|---|---|
| AMH (anti-Mullerian hormone) | Blood test, any day of the cycle |
| Antral follicle count (AFC) | Vaginal ultrasound early in the cycle to count small follicles |
| FSH and estradiol | Blood test, usually on cycle day 3 |
AMH: what it does and does not tell you
AMH is made by the small follicles that hold eggs. It is a useful guide, but it is often misunderstood. No single ovarian reserve test can definitively predict whether you will get pregnant.
- Gives an estimate of how many eggs remain
- Helps predict how the ovaries may respond to fertility medicines
- Can be high in polycystic ovary syndrome (PCOS)
- Does not measure egg quality
- Does not predict whether you will conceive, naturally or with treatment
- Does not predict when menopause will happen
A low AMH suggests fewer eggs remain, but it does not mean you cannot get pregnant. Many other factors matter, including age, ovulation, the fallopian tubes, the uterus and sperm.
When to seek help
- Under 35See a doctor after one year of regular unprotected sex without pregnancy.
- 35 and overSee a doctor after six months of trying.
- Known risk factorsIf you already know of a possible fertility problem, or have irregular periods, seek advice sooner.
Other ways age affects pregnancy
Egg numbers are only part of the picture. ASRM describes a decline that is gradual until the early 30s and speeds up after the mid-30s, alongside other age-related changes.
| Change with age | Why it matters |
|---|---|
| More chromosomal abnormalities in eggs | Higher chance of miscarriage and conditions such as Down syndrome |
| Fibroids, endometriosis and tubal disease become more common | They can make conceiving harder |
| Pregnancy complications rise | Gestational diabetes and preeclampsia are more likely |
Do not wait the full 6 or 12 months if you have absent or irregular periods, sexual problems or a history of pelvic disease. ASRM advises evaluation straight away in these cases.
Planning ahead
Knowing how age affects fertility is not a reason to panic. It is information that helps you make choices that fit your life, whether that means trying sooner, getting checked, or exploring egg freezing.
- Talk with your partner about when you hope to have children
- Remember that most couples where the woman is under 40 conceive naturally within a year
- Ask about ovarian reserve tests if you want a clearer picture, and discuss the results with a specialist
- If you are considering egg freezing, ask early, since age at freezing matters most
- Remember that fertility is shared: the male partner's health matters too
Egg freezing: what to consider
Egg freezing lets you store eggs for possible later use. It involves about 10 to 12 days of hormone injections with monitoring, then a short egg collection procedure under light anaesthesia.
- It is most likely to succeed when eggs are frozen before age 38, and works best in the 20s to early 30s
- ASRM estimates the chance that one frozen egg leads to a baby at only about 2 to 12%
- Results depend on your age at freezing and how many eggs are stored
- It is not a guarantee, and it should not create false security about delaying pregnancy
A fertility specialist can review your age, AMH and ultrasound to discuss whether egg freezing suits you and how many eggs might be realistic.
If you want children later, ASRM describes several ways to keep options open. Each has different steps, and none is a guarantee.
| Option | What it involves |
|---|---|
| Egg freezing | Hormone injections, then egg retrieval as in IVF; eggs are frozen unfertilised |
| Embryo freezing | Eggs are fertilised first; ASRM notes this is more successful than freezing eggs |
| Donor eggs or embryos | An option if your own eggs are no longer likely to work |
Your partner's age plays a part too. ASRM notes that sperm changes from the mid to late 40s can affect fertility, so plan together.
When to see a doctor
- You are under 35 and have tried for a year without pregnancy
- You are 35 or older and have tried for six months
- Your periods are irregular or have stopped
- You have had ovarian surgery, chemotherapy or radiotherapy
- Your mother or sister had early menopause
- You are thinking about egg freezing
Questions & answers
Can I take an AMH test on any day?
Yes. AMH does not change much during the cycle, so it can be checked at any time.
Does a high AMH mean I am very fertile?
Not necessarily. A high AMH can be seen with PCOS, and AMH does not measure egg quality.
Is freezing embryos different from freezing eggs?
Yes. ASRM notes that embryo freezing is well established and generally more successful than freezing unfertilised eggs, but it requires sperm at the time.
Related DBN services
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Sources
- Does My Age Affect My Fertility? — ASRM ReproductiveFacts.org
- Ovarian Reserve: Predicting Fertility Potential in Women — ASRM ReproductiveFacts.org
- Can I Freeze My Eggs to Use Later If I'm Not Sick? — ASRM ReproductiveFacts.org
- Anti-Mullerian Hormone (AMH) Test — Cleveland Clinic
- Infertility — NHS