Quality and Methodology Report 2024

1. Methodology background

Official statistic	Yes
Frequency	Annual
How compiled	Submitted by all HFEA licensed fertility clinics
Geographic coverage	United Kingdom (UK)
Register size	Approximately 100,000 cycles per annum
Document last revised	16 June 2026

2. About this quality and methodology report

This quality and methodology document contains information on the quality characteristics of the data as well as the methods used to create it. The information in this document will help you to:

• understand the strengths and limitations of the data

• learn about existing uses and users of the data

• reduce the risk of misusing data

• help you to decide suitable uses for the data

• understand the methods used to create the data

3. Important points

3.1. All licensed fertility clinics in the UK are required by law to provide information to the HFEA about treatments they carry out and their outcomes. We hold this information on our Register, which contains information about fertility patients, partners, donors, treatment and children born as a result of these treatments.

3.2. The information that we publish is a snapshot of Register data as of 06 May 2026. Results are published according to the year in which the cycle was started unless otherwise stated.

3.3. Clinics are required to submit records of all treatments and outcomes, including births. Due to the need for the HFEA to receive outcome information from the treatments and validate, and process the data received from all UK clinics, data from the HFEA will have a delay. Data on births from 2024 is preliminary and remains unvalidated.

3.4. Due to large-scale data migration project for our data Register, treatments, pregnancies and birth outcomes from 2020-21 remain unvalidated.

3.5. As our database consists of a live Register and we rely on quality of data reporting from clinics, information may be subject to change and the figures published here may differ slightly to those published before or in the future.

3.6. This publication reports national data trends over time. Clinic-specific data is published on our website’s clinic search tool, Choose a Fertility Clinic, as well as in our Fertility Sector (formerly State of the Sector) reports. Further information about the Register and data research using the Register can be found in our Data research webpage.

4. Quality summary

We make information from the Register available to patients, clinic staff, media, researchers and the public to show how fertility treatment has changed over time. We publish data from our Register on treatment and outcomes, covering treatment type, age group, partner type, ethnicity, donor information, funding status, English region and UK nations annually. The data published is a snapshot of our Register data submitted by clinics and is subject to change.

Our explorable dataset, the HFEA dashboard, shows HFEA data from 1991 onwards and provides more detailed Register data. This is updated annually with publication of our Fertility treatment: trends and figures report.

5. Quality characteristics of UK Register data

5.1. Relevance

The Human Fertilisation and Embryology Act 1990 made it a legal requirement for every licensed fertility clinic in the UK to submit information on all fertility treatments and children born as a result to the HFEA. The HFEA holds a Register of these treatments since 1991, which is believed to be the longest running database of fertility treatment in the world. We produce this statistical release on an annual basis with an underlying dataset.

Information of people who were involved in the treatment, including patients, partners, donors, surrogacy patients and children born, are included in the Register regardless of a person’s residence and may include births that occurred outside of the UK. We do not hold detailed information on partner intrauterine insemination (IUI), or treatments that takes place outside of licensed clinics which are not regulated by the HFEA. Information relating to surrogacy is limited to the fertility treatment taking place; we do not hold information on details of surrogacy arrangements.

5.2. Accuracy and reliability

Our reports typically present information at a cycle level rather than patient level. We make an estimate of the number of patients but owing to multiple and sometimes inconsistent registrations at different clinics, cycles are the default reporting method.

For a typical cycle, clinics will initially report patient registration, cycle-related information and early outcomes (including pregnancies) in line with General Direction 0005. Clinics then have 12 months to subsequently report the outcome of cycles for which they reported a pregnancy.

5.2.1. Data validation

Data validation involves quality checking data submitted from licensed clinics across the UK to verify treatment, pregnancy and birth outcome data is correctly recorded on our data Register. It is important to note that, the data on which we report has a two-year delay. This allows 12 months for birth outcomes to occur and to be reported by clinics to the HFEA.

The Register undergoes regular validation – this was last completed in January 2026, in line with a wider update to our systems and data, which occurred in 2021.

In 2021 the HFEA launched a new data submission system for licensed clinics and migrated fertility treatment and outcomes data to a new database. This data migration resulted in delays which had prevented the validation of treatment, pregnancy and outcome data. In 2026, most data migration and validation work has completed for treatments and pregnancies up to 2024 and births to 2023.

Previous releases of this data have been published as preliminary as a result of this data validation and migration work. This will have some impact on comparability of this report with previous preliminary data releases.

Treatments, pregnancy and birth outcomes for 2020-21 currently remain preliminary due to prioritising the validation of more recent complete years on the new reporting system. This data is likely to be underestimated due to missing data. For these years, pregnancy values are expected to be more representative for reported treatments. To mitigate the effect of missing outcome data, we have increased the reliability of birth rates provided in our publications by removing cycles where an embryo transfer occurred, but no outcome data was recorded (e.g., embryo transfer with pregnancy data but no birth data).

5.2.2. Birth rates

In line with changes in clinical practice and improvements in data collection, the way we calculate birth rates has changed (See section 6.2 for detailed explanation). This includes changing from using patient age at treatment to patient age at egg collection for frozen embryo transfers, requiring linking of an embryo transfer event with an earlier egg collection. Data is of a higher quality in more recent years. To accommodate for this, frozen embryo cycles where we are unable to link an embryo transfer with an egg collection event have been removed from reported numbers in this publication Fertility treatment 2024: trends and figures.

5.2.3. Differences between published sources

Small differences may occur between our reports, underlying datasets and the HFEA dashboard due to differences in data inclusion criteria, and any differences will be clarified in the accompanying notes, in this report and in the dashboard webpage. Additionally, data differences may be seen due to the live nature of the HFEA Register and the date data was prepared.

Data used to create our publications comes from our Register data. Improvements in data collection has enabled us to make methodological improvements to our data reporting, increasing accuracy and reliability. These changes were first applied in the Fertility treatment 2021: preliminary trends and figures 2021 report and have been used in subsequent data reports and HFEA dashboard updates. Detailed information about each can be found in Section 5.2.1 of the 2021 Quality and methodology report.

In the HFEA dashboard, a small number of cycles have been excluded due to data quality issues. Cycles have been removed where: sperm/egg source is unclear, pregnancy or births were recorded but embryo transfer data was missing, partner type was not recorded, and a very small number of cycles were excluded due to errors in clinic cycle information. The data provided in the HFEA dashboard may not match those provided in publications due to filters and suppression used. For example, IVF cycles in the HFEA dashboard will be slightly higher than in publications as we have not restricted data to only include cycles begun with the intention of immediate treatment.

In Sections 5.2.2 and 6.2, we outlined the changes to the methodology used to calculate birth rates in the Fertility treatment 2024: trends and figures report. This aligns with methodology used in the “more statistics” section our Choose a Fertility clinic tool. However, to enable the widest dataset to be used in customisation of the HFEA dashboard, we have used patient age at transfer in cases where frozen cycles have no egg collection event linked with an embryo transfer, rather than removing these. This means that there may be some differences between birth rates reported between these publications. The differences in birth rates due to using patient age at transfer where patient age at egg collection cannot be used is typically minor, particularly in recent years at around 1-2 percentage point differences, though this may increase depending on customisation used.

In Section 1 of the Fertility treatment 2024: trends and figures (Fertility Trends), reports on the number of births by egg and sperm source. The totals in this figure may not match totals recorded elsewhere due to exclusions of surrogacy data and cases where egg and sperm source is not recorded properly in the HFEA register.

In Section 3 of Fertility Trends, where there is a patient or record of a cycle that fits into more than one category of cycle type, we have included this in both categories. This differs from the HFEA dashboard (All cycles page) where cycles and patients are counted once, even if they fall into multiple categories.

Additionally, in Section 3 of Fertility Trends, counts of donors and cycles includes any cycles started with the intention of donating eggs including those who also underwent treatment or stored eggs or embryos within the same cycle. This differs from the Sperm and Egg donors page of the HFEA Dashboard and Section 5 of the report, where we report on the number of new donor registrations in a given year.

5.3. Coherence and comparability

5.3.1. HFEA data publications

Fertility Trends is our annual publication on national and regional trends in fertility treatments and live birth rates. Delayed data validation due to a large-scale data migration project moving our 30-year fertility Register to a new system means our published reports contain preliminary treatment, pregnancy and outcome data for 2020-21 (See section 5.2.1 on Data validation for more information). This, alongside the live nature of the HFEA Register, means that data from this report may not match other publications.

Clinic-level information is published on the HFEA Choose a Fertility Clinic, website and may differ due to different reporting periods and processes.

In publications, we suppress values under five and any calculations with numerators or denominators below five are also supressed.

In the HFEA dashboard, figures less than or equal to 7 have been suppressed and figures greater than 7 have been rounded to the nearest 5. This greater level of suppression than our publications was needed, as the filter options within dashboards increase the risk of data being combined to identify individuals. See section 5.2.2. for more information on differences between the HFEA dashboard and this publication.

Across all publications, one clinic has been removed from the analysis due to data quality issues.

5.3.2. Other published sources

Although there is no standard definition of an IVF cycle, the HFEA counts a cycle as an embryo transfer, or equivalent stage if no embryos are created. Any remaining frozen embryos used subsequently are counted as new cycles. This may differ from Integrated Care Boards or local commissioning definitions of a cycle.

We recommend that readers always view the latest version of our Fertility Trends report, which includes data going back to 1991. This is because inclusions and exclusions may change year on year as we improve our methodology. Any exclusions or inclusions are applied not just to the latest year, but to all previous years, ensuring comparability within publications.

Licensed clinics have been required to provide Register information to the HFEA since 1 August 1991. Clinics report data based on our collection forms and the information requirements have changed over time. The list of information collected from September 2021 is also available in the latest data dictionary. The Human Fertilisation and Embryology Act 2008 contained provisions enabling two women in a same-sex couple to register a birth from 1 September 2009 onwards. Where possible, historical data is provided for comparison.

HFEA data is typically presented by the year in which the treatment cycle started, not the year in which a resulting birth was reported, unless otherwise specified. Other data providers, such as the Office for National Statistics (ONS), publish birth rates according to the year the child was born. There are different ways to account for the outcomes of treatment. Our live birth data counts all births where a baby was born showing some sign of life, including those who sadly go on to die within the first month of life (neonatal deaths).

Our multiple birth data counts only births where two or more babies were born alive, including those where one or more of the babies died within the first month of life. Stillbirths – where a baby is born after 24 weeks gestation showing no signs of life – are not included in either live birth or multiple birth counts in the period covered by the reports due to the way clinic birth rates are currently reported. This means that a multiple pregnancy which results in the birth of one live baby and one stillborn baby is not counted within our data as a multiple birth. The ONS however, classes a multiple birth as a pregnancy resulting in the birth of more than one baby, whether alive or stillborn.

Clinical improvements have led to increased chances of a live birth for most patients since 1991 as freezing techniques have improved with the introduction of vitrification in lieu of slow freezing.

There is a large degree of comparability in birth statistics between countries within the UK; the regions included in the reports are based on the location of the clinic rather than patient’s residency. Internationally, we provide data to ESHRE each year following data validation to allow publication of UK fertility treatment and outcome figures alongside those of other European countries.

5.4. Accessibility and clarity

Our recommended format for accessible content is a combination of HTML web pages for narrative, charts and graphs (including alt-text), with data being provided in usable formats such as Excel spreadsheets. Underlying datasets provide more detailed statistics. Alternative formats can be requested for all tables/figures in our reports.

The HFEA dashboard has undergone an accessibility review, and improvements are ongoing. Further details may be found here.

5.5. Timeliness and punctuality

A snapshot of Register data is extracted each year and we aim to publish this data in Fertility Trends in Summer of each year. There is a two-year time delay in the data we report. This allows 12 months for birth outcomes to occur and to be reported by clinics to the HFEA.

6. Concepts and definitions

6.1. Cycles and treatment cycles

The term ‘cycle’ covers the range of reasons patients undergo fertility treatment: with the intention of becoming pregnant as soon as possible (most patients), fertility preservation (a small but growing number of patients), or with the intention of donating eggs or embryos.

The term ‘treatment cycle’ includes only those cycles where the patient recorded on their registration form that they intended to try to become pregnant as part of their treatment (IVF, DI and egg sharing cycles are always treatment cycles), instead of storing eggs or embryo for future use.

This distinction is important because it has an impact on the birth rates we report. Throughout the reports, we use ‘treatment cycles’ to assess outcomes. Birth rates are calculated for those patients that intended to become pregnant to avoid underestimating the live birth rate.

A patient may undergo a cycle for multiple different reasons, for example a patient may undergo an egg collection with the intention of having a live birth as well as donate some of the eggs collected to another patient (more commonly known as ‘egg share’).

In Section 3 of Fertility Trends, where there is a patient or record of a cycle that fits into more than one category of cycle type, we have included this in both categories. This differs from the HFEA dashboard (All cycles page) where cycles and patients are counted once, even if they fall into multiple categories.

When referring to IVF in our publications this includes both fresh and frozen IVF treatments as well as treatments using ICSI unless otherwise stated.

6.2. Birth rates and pregnancy rates

The calculation of birth and pregnancy rates includes only cycles begun with the intention of immediate treatment and only cycles where the relating outcome is recorded on the Register. Pre-implantation genetic testing for aneuploidy (PGT-A), pre-implantation genetic testing for monogenetic disorders (PGT-M) and pre-implantation genetic testing for chromosomal structural rearrangements (PGT-SR) which involve checking the chromosomes of embryos prior to treatment, have been excluded.

To give patients a clear idea of their own chance of birth or pregnancy, we present overall live birth and pregnancy rates with patient eggs only, excluding donor eggs and surrogacy to mitigate for the fact that donor eggs are likely to be frozen at a younger age and may artificially inflate the chance of a live birth.

In Fertility treatment 2024: trends and figures, we have changed the way we calculate birth rates, meaning these numbers are not directly comparable to previous reports.

In previous versions of Fertility Trends, we published pregnancy/birth rates from fresh embryo transfers by patient age, using patient age at treatment, and pregnancies/births from frozen embryo transfers as an overall rate only. However, in line with changes in clinical practice and improvements in data collection, in Fertility treatment 2024: trends and figures, we have presented birth rates from IVF treatment from fresh embryo transfers, frozen embryo transfers, and a combination of fresh and frozen embryo transfers by patient age, using patient age at treatment for fresh embryo transfers and patient age at egg collection for frozen embryo transfers. In cases where there is no egg collection event linked to a frozen embryo transfer, we have removed these cycles from the calculations. One case of a suspected submission error on the Register resulted an instance of a birth rate being removed in Figure 2.

This follows on from a public consultation on birth rate measures and aligns with wider changes to data reporting by the HFEA.

Pregnancies are counted as any cycle where foetal heart pulsations or gestational sacs are reported.

The HFEA uses per embryo transferred to measure outcomes from IVF as we believe it is the most appropriate measure of a clinic’s practices and success. This ensures multiple embryo transfers are not favoured in calculating birth rates.

The data for DI and IVF birth rates per treatment cycle are available in the underlying data tables for completeness. This measure for IVF includes cycles which begun with the intention of immediate treatment but did not reach the embryo transfer stage. There are many reasons why patients may stop treatment before the embryo transfer stage: for example, over or under reaction to the stimulation drugs, a failure to successfully fertilise any collected eggs, or other external factors in the patient’s life.

All the birth and pregnancy rates we quote in these reports are for one full calendar year when treatment was undertaken. They are calculated as follows:

1. Birth/pregnancy rate per embryo transferred: the number of live birth/pregnancy occurrences divided by the sum of embryos transferred in that year
2. Birth/pregnancy rate per treatment cycle: the number of live birth/pregnancy occurrences divided by the number of treatment cycles started.

The HFEA dashboard reports birth rates from IVF treatment cycles using donor eggs. In these cases, we have reported on birth rates using patient age at treatment, rather than donor age at egg collection. This is to allow users to view the impact on birth rates when using donor eggs. Eggs from egg donors are typically from donors under the age of 35 and without known fertility issues.

6.3. Multiple pregnancy and birth rates

The calculation of multiple birth rate includes only cycles begun with the intention of immediate treatment and only cycles where relating outcome is recorded on the Register. In contrast to birth and pregnancy rates, it includes PGT‑M/SR, PGT‑A, surrogacy cycles and all egg sources.

1. Multiple birth rate: the total number of live multiple births divided by the total number of live births

6.4. ICSI cycles

Throughout the Fertility treatment 2024: trends and figures, we do not distinguish between IVF and ICSI cycles and refer to both as IVF cycles throughout. The number of ICSI cycles carried out in a given year can be found in the HFEA dashboard and in the underlying supplementary dataset available for download at the top of the Fertility Trends report.

Prior to our Fertility treatment 2022: preliminary trends and figures report, ICSI was classified as cycles where microinjection was used in IVF treatments and an egg collection occurred. This means that the previous definition of ICSI did not capture cycles using donor eggs or thawed eggs in treatment. From the 2022 report, there is no longer a requirement for an egg collection to have occurred in the treatment, meaning the number of ICSI cycles reported is greater (approx. 4% of cycles previously defined as fresh embryo IVF from the 2021 report are fresh embryo ICSI in the 2022 report).

6.5. Reciprocal IVF

Reciprocal IVF (also known as ’shared motherhood’ or ’shared parenthood’) is where eggs are collected from one partner in a same-sex female or other LGBTQIA+ couple and fertilised with donor sperm. The resulting embryo is then transferred into the other partner’s womb, who carries the pregnancy. The HFEA does not collect data on reciprocal IVF; instead, it is estimated based on cycles meeting at least one of the following conditions:

1. A cycle not intended for immediate treatment, where eggs were collected and the patient / partner would later swap roles and meet condition 2.
2. A cycle intended for immediate treatment, where no eggs were collected and the patient / partner have swapped roles from a cycle which met condition 1.
3. A cycle intended for immediate treatment rather than storage, where it had both an egg donor and a partner registered, and these were the same person.
4. A cycle where the egg/sperm source had been recorded as partner eggs and donor sperm.

Due to the way the data is stored on the Register, for instance not having an identifier for reciprocal IVF cycles recorded, this data has previously been provided in data reports within egg donation cycles. In the new reporting database, reciprocal IVF can now be estimated and are recorded separately to egg donor cycles. It is also worth noting that reciprocal IVF represented a large proportion of donor egg and donor sperm cycles in publications prior to the Trends in egg, sperm and embryo donation 2020 report.

6.6. Distinction between donor embryos and separately donated sperm and eggs

Due to the way data is collected in clinics, we cannot easily distinguish between a patient using a donated embryo, and a patient using separately donated sperm and eggs in their treatment. As such, these have been combined in previous HFEA publications.

This distinction is discussed in detail in the Trends in egg, sperm and embryo report and accompanying Quality and Methodology report from 2020.

6.7. Donor registrations

The HFEA dashboard contains information on new sperm and egg donors. This relates to the date of the first time an individual registered as a sperm or an egg donor. When an embryo is donated, this is recorded as separate sperm and egg donor registrations.

Registrations are used rather than donations, as HFEA Register does not record information on the number of sperm donation cycles. Some donors register once, while others register several times, and so only their first registration is used to avoid overcounting.

6.8. Surrogacy

Following the launch of our new data collection system PRISM in September 2021, surrogacy cycles are split into two cycles; one where eggs and sperm are collected and mixed, and one where an embryo is transferred. Intended parent(s) is/are registered in the first IVF cycle, while surrogates are registered in the second. The HFEA changed how family types in surrogacy were reported on in 2024, further details can be found in the Quality and Methodology report 2022.

7. Methods used to produce reports using UK Register data

The data used in the Fertility treatment 2024: trends and figures report, and the annual update of the dashboard is from the Register as of 06 May 2026. A snapshot of data is pulled using Microsoft SQL and fed into Microsoft Power BI where data analysis and visualisation can take place.

The information that we publish is a snapshot of data provided to us by licensed clinics at a particular time. Guidance note 32 in the HFEA Code of Practice sets out the legal basis and requirements which govern our interaction with licensed clinics and third-party providers. We work closely with clinics and third-party systems to ensure the importance and guidance around submission of Register data is understood through stakeholder groups, workshops and sharing good practice.

In producing this report, the HFEA shared draft findings with the HFEA Authority, professional, and patient representative organisations for the purposes of sense checking interpretations on the clinical aspects and implications of these findings.

We use additional quality assurance processes, including: manually validating data submissions; carrying out regular quality assurance checks on data through the inspection process; publishing non-compliances with data quality issues in inspection reports; where relevant, reviewing quality reports and targeting clinics for audit where irregular data has been submitted.