What are the IVF success rates by age?

Like any fertility treatment, the success of IVF depends on a few factors, such as your age, the cause of infertility (if known), and medical history. 

Data from the Human Fertilisation and Embryology Authority (HFEA) indicates that the average overall pregnancy rate from IVF treatment using fresh embryo transfers and a patient’s own eggs in 2022 was 31%.

The 2022 figures also show that the pregnancy rates of IVF from fresh transfers of own eggs were:

• 42% for 18–34-year-olds

• 34% for 35–37-year-olds

• 26% for 38–39-year-olds

• 16% for 40–42-year-olds

• 9% for 43–44-year-olds

It can be reassuring to know, however, that clinics must follow the same guidelines when collecting and presenting their data. The Human Fertilisation and Embryology Authority (HFEA) regulates IVF success rates in the UK, but clinics abroad aren’t required to regulate success rates in the same way. If you’re seeking IVF outside of the UK, it’s important to research success rates according to the specific country. 

It’s also important to know that while fertility clinics can display their success rates to see how successful different fertility treatments are for helping patients conceive, they can’t tell you your individual chance of getting pregnant. So, the HFEA suggests that patients compare clinic success rates to the national average to help make informed decisions.

How are IVF success rates measured?

IVF success rates can be difficult to understand because clinics may define "success" differently. Some clinics may measure success based on: 

• pregnancy rate, or clinical pregnancy, which is when a heartbeat can be detected in the womb.  

• live birth rate, which refers to when a baby is born showing any signs of life, differs from birth rate. 

• birth rate, which is the total number of births that include both live births and stillbirths. 

To make things less confusing, the HFEA recommends using pregnancy rates to indicate how successful IVF treatment is in the UK. So, what exactly are your chances of a successful pregnancy with IVF? 

Earlier this year, the HFEA published their preliminary data on IVF as of 2021 (the most recently available data). The report shows that fertility success rates have increased over the last 30 years for all age groups. The average overall pregnancy rate from IVF increased from 10% in 1991 to 29% in 2021, but let’s look at the IVF success rate for each age group, and see how Apricity’s success rates compare.

IVF success rates under 35 years old

Fertility naturally declines with age, so people under 35 have a higher chance of conceiving — with or without IVF.

People aged 18-34 had a 41% IVF pregnancy rate in 2021, the highest pregnancy rate per embryo transferred of all age groups. 

IVF success rates at 35-37 years old

Patients aged 35-37 have a 33% pregnancy rate per embryo transfer. This increased from 8% in 1991.

IVF success rates at 38-39 years old

The pregnancy rate for patients aged 38-39 getting IVF treatment was 25% in 2021.

IVF success rates at 40-42 years old

The pregnancy rate per embryo transferred for patients aged 40-42 was 16% in 2021. That’s up from only 6% in 1991.

IVF success rates over 42 years old

In 2021, the pregnancy rate per transferred embryo for patients aged 43-50 was 6%, compared to 1% in 1991.

Apricity’s IVF success rates

So, how do Apricity's success rates compare to the national average for that same year (2021)? 43% of patients under 38 who used their own eggs got pregnant. Meanwhile, 13% of patients over 38 became pregnant — but that number shot up to 27% the following year. 

Why do IVF success rates change by age?

Women are deemed to peak at the peak of their fertility in their 20’s with this reducing into their 30’s and more rapidly after 35. IVF success rates by age differ for several reasons related to the physical changes that occur:

Ovarian reserve

This term refers to the number of eggs a woman has available for fertilisation. How many eggs a woman has is predetermined. Women are born with all the eggs they will ever have, and this number decreases with age. By the time a woman reaches her mid-to-late 30s, there is a steeper decline in the quantity of eggs remaining.

Egg quality

As a woman ages, not only does the quantity of her eggs diminish, but the quality also tends to decline. Eggs from older women are more likely to have chromosomal abnormalities, which can affect fertilisation, implantation, and the likelihood of a healthy pregnancy.

Uterine receptivity

While the uterus remains capable of carrying a pregnancy well into a woman’s 40s and even beyond, certain age-related changes can affect the uterine lining's receptivity. These changes might impact the implantation of embryos.

Increased risk of miscarriage

Older women face a higher risk of miscarriage, primarily due to the increased likelihood of chromosomal abnormalities in their eggs. This affects the overall success rates of IVF, as achieving a healthy, full-term pregnancy becomes more challenging.

Other factors influencing IVF success rates

While a woman's age (or maternal age) is a crucial part in the success of IVF treatment, there are multiple factors to consider. Other factors that influence IVF success include: 

Your overall health

Good overall health can enhance IVF success rates. Conditions such as diabetes, hypertension, and autoimmune disorders can complicate pregnancy and affect implantation and development.

The cause of infertility

Knowing the cause of infertility, such as ovulatory disorders, blocked fallopian tubes, or male factor infertility, allows for targeted treatments, improving success rates. For example, if it known that sperm motility is poor, then ICSI treatment can improve the chance of conception.

When the cause of infertility is unknown, treatment can be more challenging, potentially affecting success rates as specific issues may not be addressed.

The quality of eggs (and whether you used donor eggs)

Egg quality is a crucial contributor to IVF success. High-quality eggs, in turn, create high-quality embryos and this is important as they must be chromosomally normal and strong enough to go through the early stages of development. When egg quality is known to be poor, IVF with donor eggs is an effective alternative treatment option.

IVF with donor egg success rates are typically higher than IVF with own eggs, especially for women over 35. HFEA data from 2018 showed that using donor eggs greatly increased the chances of success for IVF treatment for older women. The quality of eggs decreases as you age, which can lower the chances of a successful IVF cycle. But if donor eggs are used, the birth rates remain high. This is because the egg donors are typically five years younger than IVF patients. For example, patients below the age of 35 had a 31% birth rate per embryo transferred in 2018, while patients 43 years and older had a rate below 5%.

Whether you used fresh or frozen embryos

A fresh embryo transfer occurs 3-6 days after egg retrieval within the same IVF cycle. A frozen egg transfer (FET) uses embryos from a previous egg cycle that have been frozen and can take place in any subsequent menstrual cycle.

In 2021, average IVF birth rates for patients aged 18-34 were 33% per embryo using fresh embryo transfers and 27% using frozen embryo transfers. However, there are studies that suggest that in some instances, and for some age groups, frozen embryo transfers increase the chance of a successful pregnancy.

Number of previous pregnancies

A history of successful pregnancies, whether through IVF or naturally, can be a positive indicator for future IVF success. Multiple miscarriages can indicate underlying issues that might affect IVF outcomes, though specific causes can often be treated or managed.

How good the fertility clinic is

IVF success rates can vary significantly between clinics and in comparison to national averages. A clinic’s success rates can be influenced by:

• Expertise and experience: Clinics with highly skilled and experienced fertility specialists and embryologists tend to have higher success rates.

• Technology and protocols: Advanced technology and evidence-based, individualised protocols contribute to better outcomes.

• Lab standards: High standards in the lab, including proper handling and culturing of embryos, are crucial for success.

• Patient demographics: Some clinics specialise in treating older women or people with specific types of infertility who are less likely to have successful treatment and this can impact a clinic’s overall rates.

Lifestyle factors

Lifestyle factors are behaviours and characteristics that you have the option to change. They impact overall health and well-being, and as such, can contribute to IVF success rates.

• Weight: Maintaining a healthy weight is important. Both underweight and overweight women may experience hormonal imbalances that influence IVF outcomes.

• Smoking: Smoking has been shown to reduce fertility and negatively impact IVF success rates. Quitting smoking can improve overall health and the likelihood of a healthy pregnancy following IVF treatment.

Diet and exercise: Fertility and nutrition are linked, and regular exercise contributes to better reproductive health and can enhance the chances of a successful IVF cycle.

Conclusion

It's good to look at success rates when choosing a fertility clinic, but it's important to keep in mind that these numbers aren't the whole story. A clinic might be turning away couples who have a lower chance of success, or they might be using more embryos per treatment cycle. 

​​Many clinics appear to have high success rates by transferring multiple embryos at once. The HFEA actually launched a campaign to decrease the number of embryos transferred to reduce risk to both the mother and baby. As a result of this campaign, the number of twin and multiple births has decreased in recent years. The HFEA Code of Practice originally stated that a maximum of three embryos could be transferred, but in 2001, it was changed to a maximum of two embryos, with three only allowed in exceptional circumstances.

Some clinics also specialise in treating certain types of infertility, which can also impact their success rates. So, it's worth doing some research and considering other factors when making your decision. Don’t be afraid to ask a clinic or fertility advisor questions!

It's understandable to want to know your chances based on national success rates or individual clinic statistics, but it's important to remember that you’re not just a number. While statistics can help you make plans and pick a clinic, your fertility journey is unique, and the level of care and support you receive from your clinic should reflect that.

At Apricity, we are proud to deliver inclusive, high-quality fertility care that results in our IVF success rates exceeding the national average across all age groups. If you’d like to find out more about the IVF process or our clinic’s success rates, you can book a free consultation with an Apricity fertility advisor today.

References

1. (n.d.). Fertility treatment 2021: Preliminary trends and figures. Human Fertilisation and Embryology Authority. https://www.hfea.gov.uk/about-us/publications/research-and-data/fertility-treatment-2021-preliminary-trends-and-figures/#section-1

2. Ibid. 

3. Amini, P., Ramezanali, F., Parchehbaf-Kashani, M., Maroufizadeh, S., Omani-Samani, R., & Ghaheri, A. (2021). Factors associated with in vitro fertilization live birth outcome: a comparison of different classification methods. International Journal of Fertility & Sterility, 15(2), 128. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052806/ 

4. (2020, June 30). Fertility treatment 2018: Trends and figures. Human Fertilisation and Embryology Authority. https://www.hfea.gov.uk/about-us/publications/research-and-data/fertility-treatment-2018-trends-and-figures/#donoreggs 

5. (n.d.). Reducing multiple births: Giving patients the best chance of a healthy baby. Human Fertilisation and Embryology Authority. https://www.hfea.gov.uk/about-us/our-blog/reducing-multiple-births-giving-patients-the-best-chance-of-a-healthy-baby/#:~:text=The%20first%20HFEA%20Code%20of,three%20only%20in%20exceptional%20circumstances.