FOI reference: FOI-2026-3686
You asked
I am writing to submit a Freedom of Information request regarding the recording and classification of deaths where hormonal contraception may have contributed to serious blood clotting events.
We are seeking information regarding how deaths involving medicines, including hormonal contraception, are recorded within mortality statistics.
Please could you provide the following information:
1. Recording of medicines on death certificates
Please confirm whether the use of a prescribed medicine is routinely recorded within mortality data where that medicine is considered to have contributed to or caused a person's death.\ If yes:
- What information is recorded?
- How is this information coded?
- Is the specific medicine name captured?
- Is the drug class captured?
- Is the reason for prescribing the medicine captured?
If no:
- Please explain how potential medicine-related causes of death are identified within mortality statistics.
2. Identification of hormonal contraception as a contributing factor
Please confirm whether ONS mortality datasets identify whether a person who died from a blood clot-related condition was using:
- Combined oral hormonal contraception
- Combined hormonal contraceptive patch
- Combined hormonal vaginal ring
- Other hormonal contraceptive methods
If this information is not collected, please confirm whether there is any linkage between mortality records and:
- NHS prescription data
- GP prescribing records
- Hospital records
- Coroner reports
- Medicines safety databases
3. Coroner information
Please confirm whether ONS receives information from coroners regarding:
- Suspected adverse drug reactions
- Medicines considered to have contributed to a death
- Hormonal contraception being considered a contributing factor
If yes, please provide details of how this information is incorporated into mortality statistics.
We said
Thank you for your request.
We compile mortality statistics from information collected at death registration. All conditions recorded on the death certificate are coded using the World Health Organization's International Classification of Diseases, Tenth Revision (ICD-10). Please see our user guide to mortality statistics for further information.
1. Recording of medicines on death certificates
Whether a prescribed medicine is captured within mortality data depends on whether it is mentioned on the death certificate or coroner documentation supplied as part of the registration process.
Where a medicine is explicitly recorded by the certifying doctor or coroner as having contributed to the death, that information is coded and stored as part of the mortality record. We code all causes and conditions mentioned on the death certificate and does not make assumptions beyond the information provided.
What information is recorded?
We record the causes and conditions stated on the death certificate, including any medicines that are specifically mentioned by the certifier or coroner.
How is this information coded?
Terms recorded on the death certificate are coded using ICD-10. In some circumstances, medicines may be assigned ICD-10 codes relating to adverse effects of drugs or poisoning. All conditions mentioned are coded and an underlying cause of death is selected using World Health Organization coding rules.
Is the specific medicine name captured?
If a specific medicine name is recorded on the death certificate or coroner information supplied for registration purposes, it may be retained as part of the coded mortality record. However, we can only capture medicines that are explicitly mentioned in the information received. We publish statistics on deaths relating to drug poisoning in England and Wales which does include information on deaths involving specific substances.
Is the drug class captured?
Drug classes are not routinely recorded as a separate mortality variable. Any information available is derived from the wording supplied on the death certificate and the resulting ICD-10 coding.
Is the reason for prescribing the medicine captured?
No. Mortality records are derived from death registration information and do not routinely contain information on why a medicine was prescribed unless that information is explicitly included on the death certificate.
2. Identification of hormonal contraception as a contributing factor
Our mortality datasets do not contain a routine variable indicating whether a person was using:
Combined oral hormonal contraception
Combined hormonal contraceptive patches
Combined hormonal vaginal rings
Other hormonal contraceptive methods
Such information would only be available if the contraceptive product was specifically mentioned on the death certificate or accompanying coroner information used in the registration process. We do not routinely collect information on contraceptive use for all deaths.
Linkage to other data sources
Our mortality records are primarily based on death registration information. Information from NHS prescription systems, GP prescribing records, hospital prescribing systems, medicines safety databases and wider clinical records is not routinely included within standard mortality statistics.
We do undertake a range of data linkage activities for research and statistical purposes. However, there is no routine mortality dataset variable identifying the use of hormonal contraception prior to death.
3. Coroner information
We receive information supplied through the death registration process where a death has been investigated by a coroner. The information available to us is limited to the details included on the coroner certificate and registration documentation provided to us. We do not routinely receive associated toxicology reports, full records of inquest proceedings or other supporting documents.
Suspected adverse drug reactions
If a coroner records an adverse reaction to a medicine as part of the cause of death information supplied for registration, that information will be coded within the mortality record.
Medicines considered to have contributed to a death
Where medicines are mentioned by the coroner as contributing to the death, those references will be coded as part of the cause-of-death coding process. We can only code information that is included in the documentation received.
Hormonal contraception being considered a contributing factor
There is no routine mortality data field identifying hormonal contraception as a contributing factor. Such information would only be available where it was explicitly recorded within the cause-of-death information supplied by the coroner or certifying practitioner.
Additional information
We code every condition mentioned on a death certificate using ICD-10 and derives an underlying cause of death according to internationally agreed World Health Organization rules. Mortality statistics are therefore dependent on the information recorded by the certifier and do not provide a complete record of all medicines a person may have been prescribed or used prior to death.