HFEA.gov.uk uses cookies to deliver content and make improvements to the website. Accept Configure Menu toggle Guide to the Anonymised Register Find out what the Anonymised Register is and how to get the most out of it. We hold the longest running register of fertility treatment data in the world. World class research has been carried out using our data, either alone or by linking to other datasets. We collect data and statistics about over 70,000 fertility treatments performed each year in the UK from 1991 to 2016. We are committed to making as much of this information available as possible to inform patients, researchers and clinicians. Data we collect includes: identifying information such as name, date and place of birth of patients, their partner and any children born as a result of treatment reasons for seeking treatment and obstetric history the type of treatment being used, the number of eggs collected, and the number of embryos transferred the number of babies born, their gestation and birthweight. Access the data-sets Download this guide If you want this guide to refer to later, or print it out you can download it as a PDF. Guide to the anonymised Register (PDF 232 KB) Click to show and hide content Using register data for research There are two main types of data which can be used: anonymised data, where no identifiers are present and some of the information is banded, or obscured, to protect patient privacy, and patient-identifying data, where the data may be very detailed, or contain actual identifiers (e.g., date and place of birth, names, address, place of treatment) allowing the records to be linked to another database. Research can only take place within the strict confines of the law, which provides very strong protection of patient, donor and offspring confidentiality (stronger still than normal medical confidentiality). Researchers who aim to use data in our Register only and not to link subjects to other datasets can use the anonymised version of the data in our Register. This anonymised dataset contains a large proportion of all the Register data going back to 1991, with the patient identifiers removed, and any secondary identifying fields aggregated or suppressed. The anonymised Register allows professionals in the sector and the wider research community to make good use of the data we collect. The anonymised Register allows researchers to access a large and rich data set, but one that does not identify any patients, or children born as a result of treatment. Click to show and hide content How useful is the anonymised register? Research using anonymised data can still answer important questions, like which factors influence treatment outcomes, or which factors indicate that a patient should have only one or two embryos transferred during treatment. In fact, due to legislative changes in 2009, researchers can have greater coverage of treatment cycles using the anonymised dataset than one including patient identifying information. Click to show and hide content Additional data fields We're not currently able to produce bespoke versions of the anonymised data with further information added (for instance a maternal identifier, or more granular data) as this increases the risk of patient identification. If you would like further information on how to gain access to more detailed data for research, please email intelligenceteam@hfea.gov.uk. Click to show and hide content Helping us get more value from the anonymised Register Although we are unable to provide detailed feedback or guidance on anonymised Register queries, we would like to hear about any projects using anonymised register data. We will use this to provide better information for patients, the public and other researchers. This also helps inform our policy and future research. Please email intelligenceteam@hfea.gov.uk to let us know of your progress. Click to show and hide content Data quality and collection We invested in our Information for Quality programme to transform the way we collect, use and publish information to benefit patients and other stakeholders. A large part of this involved developing a new data submission system and Register to improve the quality of the data we hold. This will be live from Autumn 2018. The types of forms, the information that we have collected, and the method of data collection have changed over the years so some of the data that we hold is not present across all the years of the Register or to the same degree of quality. Click to show and hide content Using the anonymised Register Opening the data The anonymised register is supplied as an excel file and split into multiple files due to the size. The file has been designed to be easily imported into a range of applications used for analysis, but we cannot guarantee this functionality. Unfortunately, we are not able to provide guidance on how you can import the anonymised Register into any applications. Please see the application help guides provided by whichever software/application you are using for details on how to import this type of file. Using the Data The anonymised Register contains 87 fields of data on treatment cycles started between 1991 and 2016. We will aim to provide an updated every 15 months (i.e. by March 2018 for the 2016 year). The content of each field is described in more detail in section 10. Data Types The anonymised Register includes 3 types of data: Number: Numeric Value Characters: Greater, Equal >= Binary Integer: True/false (1,0) Text: Alphanumeric data Data fields The anonymised Register contains 95 fields as detailed below. Field Data type Description Patient Age at Treatment Text Patient’s age at treatment, banded as follows: 18-34,35-37,38-39,40-42,43-44,45-50 Date patient started trying to become pregnant OR date of last pregnancy Number The number of years ago that patient started trying to become pregnant or years since last pregnancy Total Number of Previous cycles, Both IVF and DI Number How many treatment cycles of IVF and DI the patient has previously had Total Number of Previous treatments, Both IVF and DI at clinic Number How many treatment cycles of IVF and DI the patient has previously had at the clinic associated with this treatment Total Number of Previous IVF cycles Number How many treatment cycles cycles of IVF the patient has previously had Total Number of Previous DI cycles Number How many treatment cycles of DI the patient has previously had Total number of previous pregnancies, Both and DI Number How many time the patient has previously been pregnant, Both and DI Total number of IVF pregnancies Number How many times the patient has been pregnant through IVF Total number of DI pregnancies Number How many times the patient has been pregnant through DI Total number of live births - conceived through IVF or DI Number How many live births the patient has had through IVF or DI Total number of live births - conceived through IVF Number How many live births the patient has had through IVF Total number of live births - conceived through DI Number How many live births the patient has had through DI Type Infertility Female Primary Bit 1 if the main cause of infertility is due to the patient, 0 otherwise Type of Infertility – Female Secondary Bit 1 if the secondary cause of infertility is due to the patient, 0 otherwise Type of Infertility – Male Primary Bit 1 if the main cause of infertility is due to the partner, 0 otherwise Type Infertility – Male Secondary Bit 1 if the secondary cause of infertility is due to the partner, 0 otherwise Type of Infertility – Couple Primary Bit 1 if the main cause of infertility is due to the patient/partner problem, 0 otherwise Type of Infertility – Couple Secondary Bit 1 if the secondary cause of infertility is due to the patient/partner problem, 0 otherwise Cause of Infertility – Tubal disease Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility - Ovulatory Disorder Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Male Factor Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Patient Unexplained Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility - Endometriosis Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Cervical factors Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Female Factors Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Partner Sperm Concentration Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Partner Sperm Concentration Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Partner Sperm Morphology Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility – Partner Sperm Motility Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Cause of Infertility - Partner Sperm Immunity Bit 1 if the primary cause of infertility is as detailed, 0 otherwise Main Reason for Producing Embryos Storing Eggs Text A comma separated list of the main reason for this cycle which can include: Treatment Now, For Donation, For Storing Eggs, For Research Stimulation used Bit 1 if this was a stimulated cycle, 0 otherwise Type of Ovulation Induction Text A comma separated list of the types of stimulation used Egg Donor Age at Registration Text If donor eggs were used, the donor's age at registration banded as follows: <=20,21-25,26-30,31-35 Sperm Donor Age at Registration Text If donor sperm was used, the donor's age at registration banded as follows: <=20,21-25,26-30,31-35,36-40,41-45,>45 Donated embryo Bit 1 if this cycle used a donated embryo, 0 otherwise Patient acting as Surrogate Bit 1 if the patient was acting as a surrogate in this cycle, 0 otherwise Type of treatment - IVF or DI Text IVF or DI Specific Treatment Type Text A comma separated list of specific treatment types used in this cycle PGT-M Bit 1 if this cycle involved the use of pre-implantation genetic testing for monogenic disorders , 0 otherwise PGT-M treatment Bit 1 if this cycle would be contained in the ‘PGT-M’ CaFC category on the HFEA website, 0 otherwise PGT-A Bit 1 if this cycle involved the use of pre-implantation genetic testing for aneuploidy , 0 otherwise PGT-A treatment Bit 1 if this cycle would be contained in the ‘PGT-A’ CaFC category on the HFEA website, 0 otherwise Elective Single Embryo Transfer Bit 1 if this cycle involved the deliberate use of only one embryo, 0 otherwise Egg Source Text Indicates whether the eggs used in this cycle came from the Patient (P) or a Donor (D) Sperm From Text Indicates whether the sperm used in this cycle came from the Patient (P) or a Donor (D) Fresh Cycle Bit 1 if this cycle used fresh embryos, 0 otherwise Frozen Cycle Bit 1 if this cycle used frozen embryos, 0 otherwise Eggs Thawed Number If this cycle used frozen eggs, the number of eggs thawed Fresh Eggs Collected Number The number of eggs collected in this cycle Fresh Eggs Stored Number The number of eggs collected in this cycle and subsequently frozen Total Eggs Mixed Number The number of eggs mixed with sperm Eggs Mixed with Partner Sperm Number The number of eggs mixed with sperm from the partner Eggs Mixed with Donor sperm Number The number of eggs mixed with sperm from a donor Total Embryos Created Number The total number of embryos created in this cycle Eggs Micro-injected Number The number of eggs that were injected with sperm e.g. By ICSI Embryos from Eggs Micro-injected Number The number of embryos that were created in this cycle using ICSI Total Embryos Thawed Number If this was a frozen cycle, the total number of embryos that were thawed Embryos Transferred Number The number of embryos transferred into the patient in this cycle Embryos Transferred from Eggs Micro-injected Number The number of embryos transferred into the patient in this cycle that were created using ICSI Embryos stored for use by Patient Number The number of embryos that were created in this cycle and then frozen for subsequent use by the patient. Embryos (from Eggs Micro- injected) Stored for Use By Patient Number The number of embryos that were created in this cycle by injecting sperm and then frozen for subsequent use by the patient. Date of Egg Collection Number The number of days between egg collection and the first date provided in the series: egg collection date; egg thaw date; egg mix date; embryo thaw date; embryo transfer date Date of Egg Thawing Number The number of days between egg thawing and the first date provided in the series: egg collection date; egg thaw date; egg mix date; embryo thaw date; embryo transfer date Date of Egg Mixing Number The number of days between egg mixing and the first date provided in the series: egg collection date; egg thaw date; egg mix date; embryo thaw date; embryo transfer date Date of Embryo Thawing Number The number of days between embryo thawing and the first date provided in the series: egg collection date; egg thaw date; egg mix date; embryo thaw date; embryo transfer date Date of Embryo Transfer Number The number of days between embryo transfer and the first date provided in the series: egg collection date; egg thaw date; egg mix date; embryo thaw date; embryo transfer date Year of Treatment Number The year in which this cycle took place Live Birth Occurrence Bit 1 if there were 1 or more live births as a result of this cycle, 0 otherwise Number of Live Births Number The number of live births as a result of this cycle Early Outcome Text A comma separated list of the results of a patient scan Number of Foetal Sacs with Foetal Pulsation Number If foetal sacs were present in the scan, the number of sacs that evidenced foetal pulsation 1st Foetal Heart – Weeks Gestation Number The number of weeks of gestation for this foetal heart: banded for less that 30 weeks or greater than 40 weeks 1st Foetal Heart – Birth Outcome Text Comma separated list of the outcome of this pregnancy: Embryo reduction; live birth; miscarriage; still birth; termination 1st Foetal Heart - Birth Weight Text Banded birthweight of this child: Less than 1kg; Between 1.5kg and 1.99Kg; Between 1kg and 1.49Kg; Between 2.0kg and 2.49Kg; Between 2.5kg and 2.99Kg; Between 3.0kg and 3.49Kg; Between 3.5kg and 3.99Kg; Between 4.0kg and 4.49Kg; Between 4.5kg and 4.99Kg; Between 5.0kg and 5.49Kg; Between 5.5kg and 5.99Kg; 6kg or greater 1st Foetal Heart – Sex Text The sex of the child: Male (M), Female (F) 1st Foetal Heart – Delivery Date Number Year the child was delivered 1st Foetal Heart – Birth Congenital Abnormalities Bit 1 if a congenital abnormality was recorded, 0 otherwise 2nd Foetal Heart – Weeks Gestation Number The number of weeks of gestation for this foetal heart: banded for less than 30 weeks or greater than 40 weeks 2nd Foetal Heart – Birth Outcome Text Comma separated list of the outcome of this pregnancy: Embryo reduction; live birth; miscarriage; still birth; termination 2nd Foetal Heart - Birth Weight Text Banded birthweight of this child: Less than 1kg; Between 1.5kg and 1.99Kg; Between 1kg and 1.49Kg; Between 2.0kg and 2.49Kg; Between 2.5kg and 2.99Kg; Between 3.0kg and 3.49Kg; Between 3.5kg and 3.99Kg; Between 4.0kg and 4.49Kg; Between 4.5kg and 4.99Kg; Between 5.0kg and 5.49Kg; Between 5.5kg and 5.99Kg; 6kg or greater 2nd Foetal Heart – Sex Text The sex of the child: Male (M), Female (F) 2nd Foetal Heart – Delivery Date Number Year the child was delivered 2nd Foetal Heart – Birth Congenital Abnormalities Bit 1 if a congenital abnormality was recorded, 0 otherwise 3rd Foetal Heart – Weeks Gestation Number The number of weeks of gestation for this foetal heart: banded for less than 30 weeks or greater than 40 weeks 3rd Foetal Heart – Birth Outcome Text Comma separated list of the outcome of this pregnancy: Embryo reduction; live birth; miscarriage; still birth; termination 3rd Foetal Heart - Birth Weight Text Banded birthweight of this child: Less than 1kg; Between 1.5kg and 1.99Kg; Between 1kg and 1.49Kg; Between 2.0kg and 2.49Kg; Between 2.5kg and 2.99Kg; Between 3.0kg and 3.49Kg; Between 3.5kg and 3.99Kg; Between 4.0kg and 4.49Kg; Between 4.5kg and 4.99Kg; Between 5.0kg and 5.49Kg; Between 5.5kg and 5.99Kg; 6kg or greater 3rd Foetal Heart – Sex Text The sex of the child: Male (M), Female (F) 3rd Foetal Heart – Delivery Date Number Year the child was delivered 3rd Foetal Heart – Birth Congenital Abnormalities Bit 1 if a congenital abnormality was recorded, 0 otherwise 4th Foetal Heart – Weeks gestation Number The number of weeks of gestation for this foetal heart: banded for less that 30 weeks or greater than 40 weeks 4th Foetal Heart – Birth Outcome Text Comma separated list of the outcome of this pregnancy: Embryo reduction; live birth; miscarriage; still birth; termination 4th Foetal Heart - Birth Weight Text Banded birthweight of this child: Less than 1kg; Between 1.5kg and 1.99Kg; Between 1kg and 1.49Kg; Between 2.0kg and 2.49Kg; Between 2.5kg and 2.99Kg; Between 3.0kg and 3.49Kg; Between 3.5kg and 3.99Kg; Between 4.0kg and 4.49Kg; Between 4.5kg and 4.99Kg; Between 5.0kg and 5.49Kg; Between 5.5kg and 5.99Kg; 6kg or greater 4th Foetal Heart – Sex Text The sex of the child: Male (M), Female (F) 4th Foetal Heart – Delivery Date Number Year the child was delivered 4th Foetal Heart – Birth Congenital Abnormalities Bit 1 if a congenital abnormality was recorded, 0 otherwise ; ; Review date: 3 November 2023 Send to a friend Print this page Follow us on Twitter Opens in new window Get in touch Facebook Opens in new window Get information Find a Clinic Treatment options Donors and donation Fertility preservation About the HFEA News and press releases Privacy, cookies and accessibility Accessibility statement Freedom of information Complaints Work for us For clinics Clinic Portal Applying for a clinic licence Applying for a research licence PGT-M conditions Research and data Our data Guide to the anonymised register Research publications