• Highlights

• In the Capture-Recapture technique, IBGE researchers match the Civil Registry and Ministry of Health databases and obtain new disaggregation levels of birth and death estimates.
• In 2022, there were 2,574,556 estimated live births and the under-registration percentage was 1.31% (33,726 births), the lowest in the time series starting in 2015.
• The highest percentage of under-registration of live births was found in the North (5.14%), followed by the Northeast (1.66%), while the lowest was in the South (0.21%).
• In the same year, it is estimated that 2,546,971 births occurred in hospitals or other healthcare establishments, which is equivalent to 98.93% of the total.
• In 2022, there was an estimate of 1,561,339 deaths in the country. The proportion of under-registration was 3.65% (56,988 deaths), a higher percentage than that of the previous year (3.49%).

In addition to the totality of vital events (births and deaths) and under-registrations and underreporting, which are part of the official IBGE statistics, disaggregation by population characteristics such as age group and place of occurrence were also published. These last data are part of the institute's experimental statistics, that is, they are under methodological evaluation.

To obtain data, researchers used the capture-recapture technique. “There are two databases and we know that both are incomplete and may overlap. So we have records and reports that appear in both the Ministry of Health and in the IBGE and refer to the same vital event. Knowing these characteristics, we can match these two lists and apply the capture-recapture technique, which is using statistical modeling to estimate the probability of an individual being captured by one of the sources”, explains statistician Luiz Fernando Costa, from the IBGE Department of Population and Social Indicators.

It is from this pairing that statisticians are able to estimate the total number of vital events, such as the number of live births and deaths in a specific period and calculate the percentages of under-registration (referring to the IBGE database) and underreporting (database from the Ministry of Health).

In 2022, the estimate is of 2,574,556 live births. The percentage of under-registration of these births was 1.31%, the lowest in the time series that began in 2015. This represents 33,726 births that occurred in 2022 and were not registered within the stipulated legal period, which runs until March of the following year. In the previous year, the percentage had been 2.06% (55,417 births). “This percentage has been falling due to collection improvements, both for Vital Statistics and for the reporting of the Ministry of Health, and also the quality of our data. So we realized that we are losing fewer records or fewer reporting”, analyzes Mr. Costa.

Statistician José Eduardo Trindade claims that there is also the impact of legislative actions on this reduction in under-registrations. “In the legal framework for early childhood, it was established that Civil Registration must be carried out in interconnected units in the maternity hospitals. Then, the child leaves the hospital with the registration made. Actions like these have impacted this gradual improvement,” he notes. He also highlights that these percentages have been falling since 2015, with a small difference in 2020, when registry offices closed due to the Covid-19 pandemic.

Despite the improvement in national figures, Brazil still has significant regional differences in relation to under-registration of births. The highest percentage was found in the North (5.14%), followed by the Northeast (1.66%) and the lowest, in the South (0.21%).

For researchers, this disparity is related to the difficulty faced by populations in accessing registry offices in these regions. “In more remote, more distant locations, registering a child can take a lot of time and this is often not done. This ends up being reflected in the under-registration indicator”, says Mr. Costa.

Another difference is highlighted when observing the age groups to which the mothers belong. The highest percentages of under-registration of births are among mothers under 15 years of age (8.06%). In the case of underreporting, the proportion is higher in the group of those aged 49 (7.84%).

“Normally this younger mother goes to the health unit, but not to the registry office. This has some motivations, such as the lack of support guiding mothers in the most appropriate way to register their child to exercise their citizenship. Another factor is the wait for the father to participate, for his name to be included in the registry, which can take longer”, explains Mr. Trindade.

The study also published birth figures by place of occurrence. In 2022, it is estimated that 2,546,971 of these occurred in hospitals and other healthcare establishments, which represents 98.93% of the total.

The researchers explain that the data does not reflect the entire portion of the country's population that is not registered. It just captures the number of live births in the reference year that were registered in that period or in the first three months of the following year.

“This under-registration and underreporting can be understood as a portrait of that moment in the country, in that reference period, knowing that, as children grow, they can have access to citizenship [being registered later]. But, for international bodies, the ideal scenario is to eradicate this under-registration situation, so that it is as small as possible, i. e., that the child has access to full citizenship at birth”, highlights Mr. Trindade.

Underreporting of deaths is higher among babies up to 27 days old

In 2022, there were an estimated 1,561,339 deaths in the country. The proportion of under-registration was 3.65% (56,988 deaths) above that recorded in the previous year (3.49%). In 2015, beginning of the time series, this proportion was 4.89%. Both under-registration (12.87%) and underreporting (1.64%) were higher among babies who died within 27 days of birth.

Estimated deaths of babies under one year of age totaled 32,718 in 2022. Among the federation units, Amapá (46.31%) had the highest percentage of under-registration for this age group, while the Federal District had the lowest (0.53%). For underreporting, the highest value was in Acre (3.57%) and the lowest in Mato Grosso (0.25%).

In the same period, the estimate of deaths of persons aged over 80 was 501,339. Maranhão was the state with the highest percentages of under-registration (36.33%) and underreporting (4.04%) for this population. The Federal District (0.11%) recorded the lowest percentage of underreporting, while Rio de Janeiro (0.22%) had the lowest percentage of underreporting.

In approximately 72.01% of estimated deaths, the place of occurrence was the hospital or other health establishment, totaling 1,124,310 cases.

About the study

The Complementary Study to the Application of the Capture-Recapture Technique is an experimental study that is part of IBGE's Vital Statistics, bringing estimates of the total number of births and deaths in the country, as well as the respective under-registrations and under-notifications and their breakdowns. The data is obtained by pairing the Civil Registry Statistics (IBGE) and the Ministry of Health databases (Brazilian Information System on Live Births - Sinasc and Brazilian Mortality Information System - SIM). The indicators can be consulted for Brazil, Major Regions, Federation Units and Municipalities.