Even if abortion is recognized as an essential health care service by international human rights agreements, it is still socially and legally stigmatized in many countries. This context creates barriers to measuring the number of safe abortions. For this reason, scholars have created innovative methods to estimate the abortions rate, incidence, and prevalence.

This post will discuss mainly the methodologies used to estimate induced abortion incidence, that is the annual number of induced abortions per 1,000 women of reproductive age. By induced abortion like these abortions are performed following the guidelines of the World Health Organization. The shown definition discriminates the numbers of unsafe and spontaneous abortions (miscarriages).

Each of the methods has strengths and weaknesses that should be considered and understood before selecting one for working in a specific setting.

Guttmacher Institute  (Singh et al., 2010) has categorized these methods between direct and indirect ones, and we will follow this division:

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Direct Method

Reporting of Abortions to a Central Government Agency

It is reliable in legal settings.

Reporting of Abortions to a Central Government Agency is a method used in countries where abortion is legal. It consists of an official report by the abortion providers to an organization in charge to collect the data (Singh et al., 2010).

This system can be very effective in countries with a standard system of collection. One of the difficulties of this method is the impossibility of creating data that can be cross-country compared, as not all countries have legalized abortion services and not all databases have the same collection objective.

Advantages

  • Demographic information about abortion seekers
  • Allows having information on a regularly

Disadvantages

  • Data objectives can be multiple and that will determine the data available
  • Underreporting from the providers
  • Underreporting from the private clinics
  • Over-reporting of the number of abortions when these records are used to reclaim the payments from the government
  • Abortion practised at home cannot be counted
  • Unsafe abortions are not consider in the system
  • Not consider abortion in areas with lack of health care providers.

Studies that have used this methodology

Declining Induced Abortion Rate in Finland: Data Quality of the Finnish Abortion Register by Mika Gissler,  Veli-Matti Ulander, Elina Hemminki, Anja Rasimus.

Declining Induced Abortion Rate in Finland: Data Quality of the Finnish Abortion Register
by Mika Gissler,  Veli-Matti Ulander, Elina Hemminki, Anja Rasimus

National abortions statistics in England and Wales 2020 by Department of Health and Social Care

Surveys to people with the gestational capacity

It is more reliable in legal and socially accepted settings.

People are directly interviewed about their abortion experience through surveys that can use community-based, convenient, or random samples (Guttmacher Institute/IUSSP, 2010). Strategies such as paraphrasing questions or secret-answered techniques should be considered to handle abortion stigma (Rossier, 2003). Likewise, all interviews should receive training.

This methodology can be limited by some cultural bias as only interview self-declared women, married women, or not consider young people in the interviews. As well, it can be limited to people who live in geographically accessible areas.

Advantages

  • Obtaining demographic characteristics of the women who are reporting
  • Obtaining demographic characteristics of the women who are reporting
  • Opportunity to get detailed information about the process of abortion seeking
  • Opportunity to get information about contraceptive use before the abortion
  • Detailed reproductive histories
  • Opportunity to get information about the abortion experience

Disadvantages

  • Unsafe abortions may not be identified
  • These surveys can feel stigmatizing
  • Underreporting due to stigma and fear of legal repercussions
  • The quality of the data collected highly depends on the skills and training of the interviewer

Study that has used this methodology

A common kind of survey is

The Sealed Envelope Method: Secret Ballot Approach

It is reliable in stigmatized and/or legally restricted settings.

The Sealed Envelope Method is used to estimate abortion prevalence (The number of women who have an abortion in their life). It works as a short survey interview that each person fills anonymously.

Advantages

  • Anonymity.
  • Demographic information.
  • Report of abortion practiced at home with medications.
  • Easy data collection.

Disadvantages

  • Underreporting of abortions.
  • Unsafe abortions may not be identified.
  • Underrepresentation of rural and geographical restrictied areas.

Study that have used this methodology

Surveys of Abortion Providers

It is reliable in legal settings

Surveys of abortion providers are used in countries where the data from self-reported and records from the hospitals are not reliable, in those cases, the registered system from the abortion providers is the most complete source of information. This methodology works like a census for abortion providers (Guttmacher Institute/IUSSP, 2010).

Advantages

  • Accurate information in countries that all the abortion providers are reached.

Disadvantages

  • Underreporting due to the use of medications to practice self-abortions.
  • Depends on the abortion providers recorded information and the quality of their registers.

Surveys of providers in restricted settings

Some researchers have used this method to obtain information in countries where abortion is not fully legal. The main limitation is that we will be able to know the real number of abortion providers in the area, however, they will be able to obtain another perspective on the abortion situation (Rossier, 2003). Additionally, it is important to consider possible backlash to the providers with the publications of the results. This methodology should be used with ethical responsibility.

Advantages

  • Information about the abortion methods.
  • Understating of the process to access abortion.

Disadvantages

  • Underreporting due to the use of medications to practice self-abortions.
  • Depends on the abortion providers recorded information and the quality of their registers.
  • Underreporting of the providers that are not located by the researches.

Study that has used this methodology

Survey of Abortion Providers in Seoul, Korea by Sung-bong Hong and Christopher Tietze

Indirect Methods

Insurance Claims and Hospital Statistics

It is reliable in legal settings

Insurance claims and hospital statistics are options to calculate abortion incidence in countries where national data is not reliable. These sources, especially the insurance reimbursement reports, can give important information to estimate the number of abortions.

Advantages

  • Need to report the abortions.

Disadvantages

  • Overreporting of abortions.
  • No demographic information about the abortion seekers.
  • Abortions with medications at home cannot be considered.
  • No differentiation of induced and spontaneous abortions.

Study that has used this methodology

Estimating Australia’s abortion rates 1985-2003 by Annabelle Chan and Leonie C Sage

Model-Based Approaches to estimating Abortion

It is reliable in countries with reliable data

These are methods to estimating abortion that uses the relation between abortion and other existent data regarding fertility. These methods are depending on the available data and can offer an approximation of abortion rates. These models are valuable in setting where the lack of data is severe.

The Residual Technique

It is reliable in countries with reliable data.

The Residual Technique is used to obtain a rate of induced abortion based on data of the proximate determinants of fertility, according to the method those are: marriage, contraception, abortion, and postpartum insusceptibility.

According to Rossier, The Residual Technique has the issue of considering an universal formula to analyze fertility across different groups. This ignores the context that affects fertility (Rossier, 2003).

Advantages

  • The Residual Technique technique is used to obtain a rate of induced abortion based on data of the proximate determinants of fertility, those are marriage, contraception, abortion, and postpartum insusceptibility.

Disadvantages

  • Highly dependent on the quality of data.
  • It is possible to over or underestimation of contributing values.

A Regression Equation Approach to the Estimation of Abortion Rates

It is reliable in a restrictive context.

The regression approach is based on the strong association between contraceptive use rates and the number of lifetime abortions per woman. This model use data from contraception, contraception unmeet needs, contraception failure, and intentional pregnancy.

Advantages

  • Calculate abortion in countries where there is not quality-data available.

Disadvantages

  • Over or underreporting of abortion.

Study that has used this methodology

The Abortion Incidence Complications Method (AICM)

It is reliable in countries where abortion is highly restricted

The Abortion Incidence Complications Method (AICM) is an estimation based on the number of women treated in medical facilities for abortion complications.

Advantages

  • Provides data in restrictive settings.
  • Provides information about abortion services in the country.
  • The model can be modified to take into account changing conditions as the use of Misoprostol increased.
  • The model take into account the number of espontaneus abortions.

Disadvantages

  • No demographic information about the abortion seekers.
  • Underreporting as some abortions will be not reported as that or some people will not seek medical support.
  • Underreporting of abortions practiced at home.
  • The model uses many assumptions for this reason the result is an approximation of the abortion incidence.
  • Inputs from abortion providers perceptions.
  • Highly cost.
  • The abortion incidence will considered safe and unsafe abortion that end up in complications.

Studies that have used this methodology

Estimating the Level of Abortion In the Philippines and Bangladesh by Susheela Singh, Deirdre Wulf, and Heidi Jones.

Anonymous Third Party Reporting Method (ATPR)

It is reliable in countries where abortion is highly restricted.

Anonymous Third Party Reporting Method is a method to collect data from an abortion seeker confidant. They argue that the close friend or relieves will have important information about induce abortion, as they usually are involved in the process to find an abortion provider  (Singh et al., 2010). This abortion was developed by Rossier, she argues that it is adequate for settings where women have strong networks (Rossier, 2003).

Advantages

  • Demographic characteristics data of the abortion seeker.
  • Report of abortion practiced at home with medications.
  • Overcome underreporting for abortion stigma.

Disadvantages

  • Underreporting of people who don’t tell about their abortion to anyone.

Study that has used this methodology

Expert Estimates

It is reliable in contexts where abortion is restricted

Experts Estimate consistent on interview different specialists to understand the abortion incidence in a specific context. The expert will use available data and consistent methods to inform about the situation of a specific setting.

Advantages

  • Cost.

Disadvantages

  • Depend on the data available.
  • Requires the use of one of the other methods.

Sources

Rossier, C., 2003. Estimating Induced Abortion Rates: A Review. Stud. Fam. Plann. 34, 87–102. https://doi.org/10.1111/j.1728-4465.2003.00087.x

Singh, S., Remez, L., Tartaglione, A., 2010. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. Alan Guttmacher Institute : International Union for the Scientific Study of Population, New York (Etats-Unis).