FERTILITY - Births, Live births, Birth rates, Mean age of the mother at birth and Total fertility rate
National Statistical Institute
|Contact organisation unit|
Population and Housing Fund Statistics Department
|Contact person function|
|Contact mail address|
2, P. Volov Str.; 1038 Sofia, Bulgaria
|Contact email address|
|Contact phone number|
+359 2 9857 543
|Contact fax number|
|Metadata last certified||12 April 2021|
|Metadata last posted||12 April 2021|
|Metadata last update||12 April 2021|
The births and the children born are surveyed. Registration is done at the moment of occurrence and the number is calculated as of 31.12 of the reference year. Live births and stillbirths are covered.
Source of data on births and children born is the Unified System for Civil registration and Administrative Service of Population. Births are registered through a common USCRASP-CDS document "Birth notification".
Regional breakdown of the fertility data is done according to the country administrative-territorial division as of 31.12 of the reference year (settlements, municipalities, districts and statistical regions) based on the current address.
Live births are used for calculation of indicators, characterizing the fertility.
· Classification of Territorial Units for Statistical Purposes in Bulgaria (NUTS);
· Unified Classification of the Administrative-Territorial and Territorial Units in Bulgaria (UCATTU).
All children born with a usual residence (current address) in the Republic of Bulgaria are included.
|Statistical concepts and definitions|
"Birth” is a complete expulsion or extraction from the mother of a foetus, irrespective alive or dead, that meet the following criteria: not
a) body weight at birth of 800 grams and over and / or 26 weeks of gestation;
b) body weight at birth of less than 800 grams and / or less than 26 weeks of gestation - provided that the foetus was born alive and has lived at least 3 days.
"Alive" is a foetus who shows signs of blood circulation. In absence of such signs, the foetus is considered “dead” (foetus mortuus).
“Abortion” is a loss or interruption of a pregnancy before the foetus to meet the above mentioned criteria.
Crude birth rate is the ratio of the number of live births during the year to the average annual population in that year. The value is expressed per 1000 inhabitants.
The total fertility rate is the sum of the age-specific fertility rates for the reference year. It represents the mean number of children that would be born alive to a woman during her lifetime if she were to pass through her childbearing years conforming to the fertility rates by age of a given year.
The net reproduction rate is the ratio between the number of women who have gave a birth during the year and the daughters born during the same year taking into account the mortality. It represents the average number of daughters that will survive until childbearing ages, born to a woman if they will experience the age-specific fertility and mortality rates of the year in question, i.e. how many girls replace a mother under the reproduction conditions during the respective year.
The age of parents at birth is calculated in completed years based on the date of birth of parents and the date of event birth.
The mean age of the mother at childbearing is calculated as a weighted average within the interval between the birth of mothers generations and children birth.
Children born - live born and stillborn.
Total number of births.
Regional breakdown of the fertility data is done according to the country administrative-territorial division as of 31.12 of the reference year (settlements, municipalities, districts and statistical regions).
1888 - 2020 total number and by sex;
2010 - 2020 on the NSI website.
|Unit of measure|
Number; per 1 000 population.
|Legal acts and other agreements|
· Law on Statistics;
· Law on Civil Registration;
· Ordinance of the Ministry of Health.
· Regulation (EU) 1260/2013 of the European Parliament and of the Council on the European demographic statistics;
· Commission implementing regulation (EU) № 205/2014 laying down uniformed conditions for the implementation of Regulation (EU) No 1260/2013 of the European Parliament and the Council on European demographic statistics, as regards breakdowns of data, deadlines and data revisions;
Data are transmitted to Eurostat, UNICEF, UN ECE, World bank and other institutions on the basis of Regulation (EU) 1260/2013 of the European Parliament and of the Council on the European demographic statistics.
|Confidentiality - policy|
· Law on Statistics;
· Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.
|Confidentiality - data treatment|
Individual data are not published in accordance with article 25 of the Law on Statistics. The publishing of individual data can be performed only in accordance with article 26 of the same law.
Information is published annually according to the Release Calendar presenting the results of the statistical surveys carried out by the National Statistical Institute.
|Release calendar access|
The calendar is available on the NSI website: http://www.nsi.bg/en/node/480
Data is published on the NSI website, section Population - Demography, migration and projections in accordance with the Law on Statistics and the European Statistics Code of Practice respecting the professional independence and aimed at objectivity, transparency and equal treatment of all consumers.
|Frequency of dissemination|
|Accessibility and clarity|
News release "Population and demographic processes".
· Population and demographic processes;
· Statistical Reference book;
· Statistical Yearbook;
· Booklet "Bulgaria".
Data on Fertility are available to all users of the NSI website under the heading Population - Demography, Migration and Projections - Fertility: http://www.nsi.bg/en/node/6610
Information System Infostat: https://infostat.nsi.bg/infostat/pages/module.jsf?x_2=52
Anonymised individual data can be provide for scientific and research purposes, and for individual request according to the Rules for the provision of anonymised individual data for scientific and research purposes.
Information service on request, according to the Rules for the dissemination of statistical products and services in NSI.
|Documentation on methodology|
· Methodology on fertility: http://www.nsi.bg/sites/default/files/files/metadata/Pop_1_Metodology_births_en.pdf;
· Manual for functioning of the Unified System for Civil registration and Administrative Service of Population.
Data on fertility are presented annually to the Eurostat, UN, UNICEF, ECE, WHO and others ? questionnaires filled in annually.
At national and regional level the main data users are ministries, agencies, national organisations and local authorities.
Data is presented to scientific institutes, universities, NGOs and others based on requests.
No user' satisfaction surveys are carried out.
Data on fertility is available by sex, weight, height, consecutive number and residence of the child (different territorial levels), place and assistance at birth, multi-foetal births, age (different groupings) of the parents, year of birth of the parents, consecutive number of the mother marriage, pregnancy, citizenship and country of birth of the mother, citizenship of the father.
|Accuracy and reliability|
|Timeliness and punctuality|
Data is published up to the end of April of the year following the reference year.
Data is released according to the terms provided in the Release Calendar presenting the results of the statistical surveys carried out by the National Statistical Institute..
|Coherence and comparability|
|Comparability - geographical|
Data is collected and processed for the different territorial units using one and the same methodology and definitions.
|Comparability - over time|
Changes of the methodology and definitions for different time periods are published in the survey methodology and metadata.
|Coherence - cross domain|
|Coherence - internal|
|Cost and burden|
|Data revision - policy|
|Data revision - practice|
Source of data on births and children born is the Unified System for Civil registration and Administrative Service of Population. Births are registered through a common USCRASP-CDS ?Birth notification?.
|Frequency of data collection|
Exhaustively for all births registered during the year.
Computer files are received from the Unified System for Civil registration and Administrative Service of Population (administrative source).
Data on demographic events is checked and controlled before to be loaded in the IS "Demography".
For successful processing, the initial notification should meet the system rules on validation and control.
The processed results are validated in respect the consistency of a single table and between the tables.
Data is processed by the IS "Demography" according to the rules for validation and control of the demographic events.