Quality report (OSF): Sterilisations
Data description
Statistical presentation
The statistics on sterilisations contain data on all sterilisations annually performed in Finland. All health care units are required to report the procedure to the Register on Sterilisations at the Finnish Institute for Health and Welfare (THL) according to a specific data collection form (ST2 form). Providing data for the register is mandatory and based on the Act on the Finnish Institute for Health and Welfare (668/2008) and the Act (283/1970 and the Decree (427/1985) on Sterilisations.
Data on the number of sterilisations is available from the year 1951 onwards. Since 1987, data on sterilisations have been kept in an electronic THL database. The data reported in this statistical report refer to the year 2025. The obligation to report the procedures to THL is continuous and the register form should be sent to THL within one month of the procedure. THL publishes the statistics once a year, during the spring following the statistical year reported.
The statistic is aimed at health care practitioners, authorities, planners and researchers working with reproductive health who need up-to-date information on sterilisations.
Relevance
The statistics contain data for the research, development, and organization of services related to reproductive health. Supplementary data is available from e.g. the Care Register for Health Care. The register on sterilisations is used for research and monitoring.
When the collection of sterilisation statistics began, the purpose of the register was to monitor the implementation of the Sterilisation Act. Today, however, the number of sterilisations has decreased, and maintaining a separate register for them is no longer considered necessary in all respects. The Finnish Institute for Health and Welfare (THL) has proposed abolishing the sterilisation register, but doing so requires an amendment to the Sterilisation Decree. For the time being, the decree has not been amended, and submitting sterilisation notifications (ST2) to THL remains mandatory.
Data content of the statistics
The statistics include all sterilisations performed in Finland. All health care units performing sterilisations are required to report the procedure to THL.
Sterilisation refers to a procedure performed on a person’s reproductive organs that results in permanent infertility. A procedure involving the reproductive organs is not regarded as sterilisation if it is necessary for the treatment of a disease of the reproductive organs or a related condition.
The data content of the Register on Sterilisations is based on the so-called ST2 form confirmed by the Ministry of Social Affairs and Health degree (1063/2008, which includes the new forms confirmed by amendment 624/2023 as annexes).
The statistics on sterilisations are provided by sex and age group per 1000 persons of the same age. The statistics also present numbers and percentages of grounds for sterilisations.
The age of the person is the age at the time of the sterilisation. The relative numbers are mainly in proportion to women of fertile age, or between 15 and 49 years of age and to women of the same age. The average population is used for population ratios.
The data for each wellbeing services county is based on the person’s municipality of residence.
Statistical processing
Source data
The statistics is based on THL’s Register on Sterilisations, which includes information on all sterilisations performed in Finland. The register contains the personal identity code of the person to whom the procedure is performed.
The register data is supplemented with the data from the Population Information System if information on municipality or the civil status of the person identity code missing.
Data collection
According to the legislation (Act on Sterilisations 283/1970, Decree on Sterilisations 427/1985), the health care unit performing the procedure is required to report the sterilisation to THL within one month using a specific data collection form approved by the Ministry of Social Affairs and Health.
Information on procedure is sent to THL electronically either as a patient information system extract or with a separate electronic form. Year 2025 most data were collected to THL by electronic means and occasional paper forms were saved electronically at THL. The unit preforming the procedure must always submit a separate notification to the Register on Sterilisations; simply making a normal entry in the patient information system in connection with the procedure is not sufficient.
Data in the 2025 statistical report is based on reports submitted to THL by 6th April 2026. THL accepts register forms also after the publication of the statistics. In these cases, the information is updated in connection with the next statistical publication.
Data submitted as database extracts are sent to THL monthly using THL Tiedontoimituspalvelu (TTP). Notifications with the electronic form are received throughout the year continuously.
Data validation
THL strives to check and correct the data as extensively as possible. The aim is to identify missing and incorrect data. Data validation checks are carried out regularly, and unclear cases are reviewed using THL’s Care Register for Health Care whenever possible.
Data compilation
THL has developed automatic measures for correcting and updating the data. Automatic corrections to the dataset are made on the basis e.g. of other information related to the sterilisation. Missing data on municipality, civil status and information on previous births are supplemented partly automatically and partly on a case-by-case basis from the Population Information System. Corrections are made on a case-by-case basis when reliable automatic reasoning is not possible.
3.5. Data revision
Data from previous statistical years is updated retroactively, if necessary, in connection with the next statistical publication. The impact of retrospective corrections on the figures has been mainly seen to be minor. For example, the 2024 data published earlier was corrected when publishing the data for 2025 and the number of sterilisations grew by 11 cases.
Quality assessment of the statistics
Accuracy and reliability
The Register on Sterilisations is based on the information the health care units send to THL and the correctness of data depends on the quality of the data submitted to THL.
For the 2025 data, it is known that the coverage of the register is incomplete for certain health care units, but the total number of procedures is consistent with the data in THL’s Care Register for Health Care. Nevertheless, the coverage of the register should be interpreted with caution.
In 2006, the coverage of the register of sterilisations was studied with the help of the Care Register for Health Care1 . The study found that 95.5 per cent of all sterilisations carried out in Finland have been reported to the register of sterilisations. Data submitted to the register indicates that the total number of sterilisations in Finland have been falling since the mid-1990s. This trend is due in part to smaller age groups and improved contraceptives, but the study also found gaps in the reporting of sterilisations. The validation study with 2011 data showed that the coverage of the Register on Sterilisations is still good but declined to 90 per cent2. In recent years, increasing numbers of male sterilisations have been performed in private health care, and statistical coverage cannot be guaranteed.
Any errors identified in the statistics will be corrected. Even earlier statistics are updated in case of delays in reporting. These revisions do not usually, however, have any significant impact on the overall trend in the number of sterilisations.
The detailed data content of the register and variable-specific quality observations are available in the Data resources catalogue.
Timeliness and punctuality
The statistics on sterilisations are produced by THL annually. The report, published once a year in the spring, describes the number of sterilisations in the previous year.
Coherence and comparability
Since 1987, data on sterilisations have been kept in an electronic THL database. Official statistical publications by the National Board of Health (one of THL’s predecessors) have been used as a source of information for earlier years.
Data for earlier years have been checked, for instance, by removing data that had been entered twice and by adding missing cases, so some data may deviate from previously published statistics.
With regard to age-specific data, it should be noted that from 1994 onwards such data in the register refer to the age of the patient on the day of the procedure, where-as the data for the years 1987–1993 refer to the age at the end of the year.
The concepts and definitions related to sterilisation have remained unchanged throughout this time.
In the data collection form for the register, for some of the variables (e.g. contraceptive method, method of sterilisation, indication) it is possible to select more than one alternative. This should be taken into account when examining the data.
The Sterilisation Act was amended in 2023. The amendment came into effect on April 3, 2023, and after this, sterility is no longer a requirement for gender confirmation. An updated registration notification form (ST2) came into effect September 1st 2023. More information on data collection form can be found on THL web pages (in Finnish).
Institutional mandate
The production of the statistics on sterilisations is based on the Act on the Finnish Institute for Health and Welfare (688/2008) and the Act on Sterilisations (283/1970). One of the official tasks of the Finnish Institute for Health and Welfare is to produce statistical data on the health and welfare of the population, the factors affecting them, and the use and functioning of healthcare and social welfare services to support decision-making, development and research. THL’s statistical production practices are guided by the instructions, recommendations and regulations of Eurostat and the Official Statistics of Finland as well as the principles of statistical ethics.
Data sharing and publishing
The statistics are published on the website of the Finnish Institute for Health and Welfare (THL). THL publishes the data at the time indicated in advance in the statistics publication calendar. The data is made public to all users at the same time.
Data related to the statistics are also published as Sotkanet indicators.
The release of the statistics report on the THL website is also accompanied by database reports on sterilisations. Database reports, or summaries and data cubes, enable users to make their own selections and retrieve information from register data.
Statistical data is annually published also in international statistical publications (NOMESCO, WHO, UN).
The statistics published by THL are public. However, the register data is confidential. The Finnish Social and Health Data Permit Authority Findata grants permits for using the data in the Finnish register on sterilisations based on the Act on the Secondary Use of Health and Social Data (552/2019).
Confidentiality
As an authority, the Finnish Institute for Health and Welfare has the obligation to produce compiled data on the health and well-being concerned with the entire country. The data used to draw up THL’s statistics is primarily confidential, and personal data may not be published. The protection of processed data is based on the Act on the National Institute for Health and Welfare (688/2008), the Statistics Act (280/2004), the Act on the Openness of Government Activities (621/1999), the EU General Data Protection Regulation (EU) 2016/679 and the Data Protection Act (1050/2018) as well as other regulation guiding the activities of the Institute.
THL’s datasets are secured at all stages of processing. Data and information systems can only be accessed by persons who have a permit to access certain data for clearly defined purposes. Others do not have the ability to view, process, change or delete data. Written instructions have been drawn up to ensure the data protection of completed statistics. All THL personnel are bound by a confidentiality obligation. The privacy notice of the register can be viewed online at thl.fi.
Special issues concerning the 2025 statistics
For the 2025 dataset, it is known that the Register on Sterilisations register contains hospital‑level gaps in completeness, but the total number of procedures is consistent with the data in THL’s Care Register for Health Care. Nevertheless, the coverage of the register should be interpreted with caution.