Age and Fertility: What Changes and How We Can Help
Clinical content by Trevor Wing MBRCP FRCHM MBAcC BSc (Hons) MSc (Dist) DMed (Img). Last reviewed October 2026.
Key facts
- A woman’s fertility starts to decline slowly in her early 30s and more steeply after about 37.
- This is mainly due to falling egg numbers and egg quality, which also increases the chance of miscarriage.
- NICE advises seeking help after 6 months of trying if you are 35 or over, and sooner if you are over 40.
- AMH and day 2 to 3 hormone tests give an indication of ovarian reserve but cannot predict natural conception on their own.
- Cycle tracking, ultrasound monitoring and a healthy lifestyle help make the most of every cycle.
How does age affect fertility?
Women are born with all the eggs they will ever have. A baby girl has around 1 to 2 million eggs at birth, about 300,000 to 500,000 at puberty and around 25,000 by her late 30s. As numbers fall, the proportion of eggs with chromosome problems rises. This means it can take longer to conceive and the chance of miscarriage increases.
Most couples under 35 who have regular unprotected sex will conceive within a year:
| Time trying | Chance of conceiving (under 35) |
|---|---|
| 3 months | about 57% |
| 6 months | about 72% |
| 1 year | about 85% |
| 2 years | about 93% |
After 35 these chances fall, and after 40 natural conception is less likely, though still possible for many women.
What other factors affect fertility as women get older?
- Conditions that become more common with age, such as endometriosis, adenomyosis and fibroids
- Damage to the fallopian tubes from past infections such as chlamydia, which often cause no symptoms
- Health and lifestyle: weight, smoking, alcohol and stress
- The male partner’s age and sperm quality, which also decline, though more gradually
What tests can show how my fertility is changing?
- AMH (anti-Müllerian hormone): a blood test, taken on any day of the cycle, that reflects the number of eggs remaining.
- FSH and oestradiol on day 2 to 3 of the cycle: a raised FSH suggests reduced ovarian reserve.
- Antral follicle count: an ultrasound count of small follicles in the ovaries, which we can perform at our clinic.
- Ovulation tracking: blood tests, basal body temperature charts and ultrasound monitoring of follicle growth.
These tests help predict how you might respond to fertility treatment, but a low result does not mean you cannot conceive naturally.
When should I seek help?
NICE advises seeing a doctor if you have not conceived after a year of trying if you are under 35, after six months if you are 35 or over, and straight away if you are over 40 or have a known fertility problem such as irregular periods or endometriosis.
What are the conventional treatment options?
- Ovulation induction with medication
- Intrauterine insemination (IUI)
- Stimulated IVF, with the goal of harvesting eggs from all the antral follicles on each ovary
- Natural-cycle IVF, where the single egg your body produces each month is collected without stimulation drugs
- IVF with donor eggs, which has the highest success rates for women in their 40s
How do we support fertility at the Women’s Natural Health Clinic?
We aim to give you the best chance in every cycle, working alongside your GP or fertility clinic. Your plan may include:
- Ovarian reserve and cycle assessment, including antral follicle count on our GE Voluson S10 3D ultrasound scanner
- Cycle tracking and timing: having sex every other day in your fertile window, which is days 10 to 17 of a 28-day cycle, gives the best chance.
- Chinese herbal medicine and acupuncture tailored to your pattern, to support cycle regularity and wellbeing during fertility treatment and improve endometrial receptivity to embryo implantation.
- Fertility herbal medicine to increase follicle counts and the success of IVF.
- Preconception nutrition and lifestyle advice for both partners.
The evidence on herbal medicine and acupuncture for age-related fertility decline is limited, so we will be clear about what they can and cannot do and help you plan the right time to move to fertility treatment.
Frequently asked questions
Can I get pregnant naturally at 40?
Yes, many women do, although it may take longer and the chance of miscarriage is higher. Seeking advice early helps you make the most of the time available.
What is a normal AMH level for my age?
AMH falls with age and varies between laboratories. It indicates egg quantity, not quality, so it is best interpreted alongside your age, cycle and ultrasound findings.
Does male age affect fertility?
Yes, though less than female age. Sperm quality declines gradually, and older male age is linked to a longer time to conceive and a slightly higher miscarriage risk.
How often should we have sex when trying to conceive?
Every other day in your fertile window, which is days 10 to 17 of a 28-day cycle. You do not need to time sex exactly to ovulation.
Book a consultation
To book, book an appointment online or call 020 3811 8778. Initial consultations last up to one hour at our clinic at 16 Bridle Lane, St Margaret’s, Twickenham TW1 3EE.