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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.

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.

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.

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.

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.

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.

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

PGD

Bit

1 if this cycle involved the use of preimplantation genetic diagnosis, 0 otherwise

PGD treatment

Bit

1 if this cycle would be contained in the ‘PGD’ CaFC category on the HFEA website, 0 otherwise

PGS

Bit

1 if this cycle involved the use of preimplantation genetic screening, 0 otherwise

PGS treatment

Bit

1 if this cycle would be contained in the ‘PGS’ 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

 

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Review date: 18 October 2020