Ovarian reserve: definition and meaning
Ovarian reserve is the number of eggs remaining in the ovaries, which declines with age from birth onward. It is estimated with blood tests such as anti-M眉llerian hormone (AMH) and FSH, and an ultrasound count of small follicles (antral follicle count). It helps predict response to IVF medication, but does not reliably predict your natural chance of getting pregnant.
How ovarian reserve changes with age
| Age | Approximate eggs remaining |
|---|---|
| Before birth (20 weeks of pregnancy) | 6 to 7 million |
| Birth | 1 to 2 million |
| Puberty | 300,000 to 400,000 |
| Age 37 | about 25,000 |
| Menopause | fewer than 1,000 |
Only around 400 to 500 eggs are ever ovulated. The rest naturally fade each month, whether you ovulate, take the pill or are pregnant.
How it is tested
- AMH: made by small follicles; a blood test on any cycle day.
- Antral follicle count: an ultrasound counts small follicles early in the cycle.
- FSH and estradiol: day 2 to 5 blood tests; high FSH suggests lower reserve.
What it does and doesn't tell you
Ovarian reserve tests are useful for planning IVF doses and predicting how many eggs egg retrieval may yield. But large studies show a low AMH does not mean you can't conceive naturally in the coming months, and a high one does not guarantee fertility. Egg quality, mostly linked to age, matters more.
The emotional weight of a number
A low result can feel frightening. Ask your doctor what it means for your specific plans before drawing conclusions. If you are not trying to conceive, testing "just to know" can cause worry without changing anything.
If you are under 35 and have tried for a year, or 35 or over and have tried for 6 months, ask for a fertility assessment. Periods stopping before 40 should be checked for premature ovarian insufficiency.
Frequently asked questions
Can I improve my ovarian reserve?
No treatment increases the number of eggs. Not smoking and protecting overall health help egg quality.
Do birth control pills save eggs?
No. The pill pauses ovulation but does not slow the natural loss of eggs. It can temporarily lower AMH readings.
Sources
- Steiner AZ et al. Association between biomarkers of ovarian reserve and infertility among older women of reproductive age. JAMA (2017)
- ACOG: Evaluating infertility
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
What is anti-M眉llerian hormone (AMH)?AMH is a hormone made by small ovarian follicles. What an AMH level tells you about ovarian reserve, what it can't tell you, and when doctors test it.
What is premature ovarian insufficiency (POI)?Premature ovarian insufficiency (POI) is when the ovaries stop working normally before age 40. Signs, causes, diagnosis, and why hormone treatment matters.Infertility: definition and meaningInfertility means not getting pregnant after 12 months of regular unprotected sex, or 6 months if you're 35 or older. Causes, tests and next steps.What is IVF (in vitro fertilization)?IVF (in vitro fertilization) joins eggs and sperm in a lab, then places an embryo in the uterus. The steps, who it helps, and how due dates work.Egg retrieval: definition and meaningEgg retrieval is the IVF step where mature eggs are collected from the ovaries with a fine needle. How it works, recovery, and the signs that need a call.