Short answer
Age is one of the most important factors in IVF success: the chance of a birth from each embryo transferred falls steadily from the mid-30s and sharply after 40 when a woman uses her own eggs.1 In UK data for 2022, the birth rate per embryo transferred was about 35% for women under 35 but about 10% at 40 to 42 and 5% at 43 to 44.1 The decline mainly reflects the age of the eggs, so success rates with donor eggs from younger women do not show the same fall.23
Key points
- The fall in success is gradual through the 30s and steeper after 40.1
- Both the number and the quality of eggs decline with age.3
- Over 42, live-birth rates per cycle with own eggs were below 4% in a large UK study.2
- With donor eggs, success did not differ by the recipient’s age.2
- NHS eligibility criteria in England also change at 40 and 42.4
How success rates change with age
The Human Fertilisation and Embryology Authority (HFEA), the UK regulator of fertility treatment, publishes national figures. Its preliminary data for 2022 show the following birth rates for each embryo transferred in fresh IVF cycles using the patient’s own eggs.1
| Age of patient | Birth rate per embryo transferred |
|---|---|
| 18 to 34 | 35% |
| 35 to 37 | 26% |
| 38 to 39 | 18% |
| 40 to 42 | 10% |
| 43 to 44 | 5% |
The HFEA describes patient age as one of the most important factors in whether treatment succeeds, and notes that the decline in success with age is a reason not to delay seeing a GP or fertility clinic.1 These figures are averages across all clinics and causes of infertility, so an individual’s own chances may be higher or lower.
Why age matters so much
A woman is born with all the eggs she will ever have, about 1 to 2 million, and only around 200,000 to 400,000 remain by puberty.3 Fertility declines because both the number and the quality of eggs fall with age. As eggs age, their chromosomes are more likely to be imbalanced, and such imbalances account for an estimated 70 to 80% of miscarriages.3
IVF cannot reverse egg ageing. A fertility education leaflet published through the European Society of Human Reproduction and Embryology (ESHRE) states that by their mid-40s most women can no longer become pregnant either naturally or with assisted reproduction using their own eggs.3
Chances over several cycles
Rates per embryo or per cycle can understate a person’s overall chance, because many people have more than one attempt. A study of 156,947 UK women treated between 2003 and 2010 looked at the chance of a live birth over successive cycles.2
| Group (own eggs) | Live birth in first cycle | Estimated live birth by sixth cycle |
|---|---|---|
| Under 40 | 32.3% | 68.4% |
| 40 to 42 | 12.3% | 31.5% |
| Over 42 | Below 4% in every cycle | Not reported |
This large national dataset gives Strong evidence that age has a major effect on IVF outcomes. The figures come from treatment given between 2003 and 2010, so they show the pattern rather than current chances.
Donor eggs and the role of egg age
The clearest evidence that egg age drives the decline comes from donor-egg treatment. In the UK study, women using donor eggs showed no difference in success by age.2 Donor eggs usually come from women under 35.3 This is why donor eggs may be discussed when someone is unable to conceive with their own eggs, although using them raises its own medical, emotional and legal considerations.
How age affects NHS access in England
NICE guidance recommends offering women under 40 an initial 3 full cycles of IVF if they meet the criteria, and considering up to 3 further cycles after discussing the chance of success.4 Women aged 40 or 41 may be offered 1 full cycle if they have not had IVF before, and IVF is offered up to the 42nd birthday.4 NICE also advises taking ovarian reserve (an estimate of the remaining egg supply) into account when discussing IVF.4 Local funding bodies decide what is actually available, and some add criteria such as weight or smoking status.5
Common questions
At what age does IVF success start to fall?
From the mid-30s. In 2022 UK data, birth rates per embryo transferred fell from 35% under 35 to 26% at 35 to 37 and 18% at 38 to 39.1
Does using frozen embryos from when I was younger help?
Possibly. The evidence points to the age of the eggs as the main factor, which is why donor eggs from younger women do not show the age-related decline.23 Individual chances with stored embryos depend on their number and quality, which a clinic can discuss.
Are clinic success rates comparable with these figures?
Only if they are reported in the same way and for the same age group. The HFEA notes that its recent birth outcome data are preliminary, which shows how timing and method affect the numbers.1
Is it only a woman’s age that matters?
No. The NHS lists other factors that affect success, including the cause of the fertility problem, body mass index, smoking and drinking.5
Bottom line
With a person’s own eggs, IVF success falls steadily through the late 30s and steeply after 40, because egg number and quality decline. Several cycles raise the overall chance at any age, but they cannot fully make up for egg ageing, which is why age is central to any discussion of IVF.
Related reading
- IVF guide
- How Many IVF Cycles Might Be Needed?
- What Does an AMH Test Tell You?
- What Should You Know About Egg Freezing?
- What Is Donor Egg IVF?
Sources
- Human Fertilisation and Embryology Authority (HFEA). Fertility treatment 2022: preliminary trends and figures. HFEA; 2024. https://www.hfea.gov.uk/about-us/publications/research-and-data/fertility-treatment-2022-preliminary-trends-and-figures/. Accessed 5 November 2026.
- Smith ADAC, Tilling K, Nelson SM, Lawlor DA. Live-birth rate associated with repeat in vitro fertilization treatment cycles. JAMA; 2015. https://doi.org/10.1001/jama.2015.17296
- International Reproductive Health Education Collaboration. Female fertility and age. ESHRE; n.d. https://www.eshre.eu/-/media/sitecore-files/SIGs/GSCA/IRHEC/Leaflets/ESHRE—Female-fertility-and-age.pdf. Accessed 5 November 2026.
- National Institute for Health and Care Excellence (NICE). Fertility problems: access criteria for in vitro fertilisation (IVF). NICE guideline NG257. https://www.nice.org.uk/guidance/NG257/chapter/access-criteria-for-in-vitro-fertilisation-ivf. Accessed 5 November 2026.
- NHS. IVF. NHS website; 2025. https://www.nhs.uk/tests-and-treatments/ivf/. Accessed 5 November 2026.
Article history
- — First published.