How Fertility Changes With Age
Female fertility is closely linked to ovarian reserve — the number and quality of eggs in the ovaries. Both decline gradually from your 20s, more noticeably from age 32, and accelerate after 37. By 40, the chance of conception per cycle is around 5%, compared to 20-25% in your late 20s. The main reason is egg quality: as eggs age, they are more likely to have chromosomal abnormalities, leading to lower fertilisation rates, higher miscarriage rates and slightly higher risk of conditions like Down syndrome. Male fertility also declines with age but more gradually, beginning around 40-45.
Realistic Timelines and Expectations
At age 30, around 75% of women trying to conceive achieve pregnancy within a year and 91% within four years
At age 35, around 66% achieve pregnancy within a year and 84% within four years
At age 40, around 44% achieve pregnancy within a year and 64% within four years
Miscarriage rates rise from 10% in your 20s to 20% at 35, 40% at 40 and 80% at 45
IVF success rates per cycle drop from around 40% in your early 30s to under 5% after 42 using your own eggs
These are averages — individual outcomes vary widely based on overall health and ovarian reserve
When to Seek Help
If you are 35 or older and have been trying for 6 months without success (versus 12 months for under-35s)
If you are 40 or older, seek help immediately when you start trying — do not wait
If you have any history of irregular periods, endometriosis, PCOS or pelvic surgery
If you have known fertility-affecting conditions (e.g., previous chemotherapy, recurrent miscarriage)
If your partner is over 45 or has a history of fertility issues
Investigations and Treatment Options
Initial testing: AMH (anti-Müllerian hormone) and antral follicle count to assess ovarian reserve, plus standard fertility blood tests
Semen analysis for the male partner — essential at any age
Investigations of the fallopian tubes (HSG or HyCoSy) to rule out blockage
Lifestyle optimisation: weight, nutrition, alcohol, smoking, sleep — all matter more after 35
Ovulation induction or IUI: Suitable for some couples but success rates are lower than IVF after 35
IVF with PGT-A: In vitro fertilisation with chromosomal screening of embryos can improve outcomes
Donor eggs: Highly successful option (50-60% per cycle) when own egg quality is the main barrier
Embryo freezing: Even one IVF cycle now can preserve embryos for later use