IVF Success Rates by Age: The Numbers You Need to Know

The age bands: what the HFEA reports

The HFEA publishes IVF success rates broken down into age groups: under 35, 35–37, 38–39, 40–42, and 43 and over. These aren't arbitrary brackets — they reflect the biological reality of how egg quality changes over time. Each step up represents a meaningful drop in both egg quantity and, more importantly, the proportion of chromosomally normal eggs.

Under 35: the strongest odds

Women under 35 have the highest IVF success rates. The average live birth rate per embryo transfer across UK clinics is approximately 32–40%. Per egg collection — the more honest measure, because it includes cycles where no embryo was suitable for transfer — it's around 28–35%.

At this age, ovarian reserve is typically good, egg quality is high, and the proportion of chromosomally normal embryos is at its peak. Most women under 35 produce 10–15 eggs per stimulation cycle, giving embryologists a good selection to work with. If you're in this age group and your first cycle doesn't work, frozen embryo transfers from the same collection offer additional chances without another egg retrieval.

35–37: still strong, first signs of decline

The birth rate per embryo transfer for women aged 35–37 is approximately 25–33%. The decline from the under-35 group is noticeable but not dramatic. Most women in this bracket still respond well to stimulation and produce a reasonable number of eggs.

The subtle shift at this stage is in egg quality rather than quantity. You may still collect 8–12 eggs, but a slightly higher proportion will have chromosomal abnormalities, meaning fewer will develop into viable blastocysts. The attrition from egg to embryo is a little steeper. Clinically, this is the age range where consultants start to be more conscious of time — if 3 IUI cycles haven't worked, the recommendation to move to IVF comes faster.

38–39: the inflection point

This is where the data shifts noticeably. Birth rate per embryo transfer drops to approximately 18–25%. Per egg collection, it's around 15–20%. The decline isn't linear — it accelerates in the late thirties.

At 38–39, ovarian reserve begins to decline more visibly. Egg collection numbers may drop to 6–10 per cycle, and the proportion of chromosomally normal embryos falls further. It's common to collect 8 eggs, fertilise 6, and end up with 1–2 viable blastocysts. That's not a clinic failing — it's biology. The key number to focus on isn't eggs collected but blastocysts formed, and ultimately, the birth rate per cycle started.

For patients in this bracket, cost per live birth becomes an especially important metric. A clinic with a 22% birth rate at £7,000 per cycle gives a cost per live birth of roughly £31,800. A clinic with an 18% rate at £5,000 gives £27,800. The cheaper headline price leads to a cheaper outcome — but only if the success rate difference is small. Run the numbers for each clinic in your age group before deciding.

40–42: lower odds, but not zero

Birth rate per embryo transfer for women aged 40–42 is approximately 10–15%. Per egg collection, it's typically 8–12%. These numbers feel discouraging, and they should be approached honestly — but they're not zero, and many women in this age group do have successful IVF pregnancies.

The challenge is that egg quality declines significantly after 40. A higher proportion of embryos will be chromosomally abnormal, leading to lower implantation rates and higher miscarriage risk. Clinics may recommend PGT-A genetic testing at this age to select chromosomally normal embryos for transfer — though the evidence on whether PGT-A improves live birth rates per cycle started is still debated.

Multiple cycles are often needed. Some clinics offer multi-cycle packages that can reduce the per-cycle cost if you're expecting to need 2–3 attempts. At this age, it's worth asking about both the per-cycle rate and the cumulative rate over 3 cycles — which can be 25–35%, a much more encouraging number.

43 and over: the honest picture

For women aged 43 and over using their own eggs, the live birth rate per cycle is approximately 2–5% at most UK clinics. Some clinics don't publish age-specific data for this group because the numbers are so small that they're statistically unreliable.

This is the age group where the conversation often shifts to donor eggs. Using eggs from a younger donor dramatically changes the success rate — birth rates with donor eggs are typically 30–45% regardless of the recipient's age, because it's the egg's age that drives outcomes, not the uterus. It's a difficult conversation, but the data is unambiguous: for most women over 43, donor eggs offer a significantly higher chance of a live birth.

Why age matters more than clinic choice

This is the uncomfortable truth. The difference in success rates between the best and worst clinics for a given age group is typically 10–15 percentage points. The difference between age groups is 20–30 percentage points. A 32-year-old at an average clinic will almost always have better odds than a 41-year-old at the best clinic in the country.

That doesn't mean clinic choice is irrelevant — it absolutely matters, especially within your age group. But it does mean that time is a factor. If you're 36 and considering IVF, starting at 36 with an average clinic gives better odds than waiting until 38 to find the 'perfect' clinic. The data is clear on this.

How to use age-specific data when comparing clinics

When comparing clinics, always look at the birth rate for your specific age band — not the clinic's overall rate. A clinic that treats predominantly younger patients will have an inflated headline number. A clinic that takes on more complex cases with older patients may have a lower average but deliver excellent results for your age group.

On Vero Fertility, we show birth rate per egg collection broken down by age band for every UK clinic, alongside verified pricing. That lets you calculate the cost per live birth for your age group at each clinic — the most useful single number for deciding where to have treatment.