Abstract

Introduction

Abortion research faces great challenges even in countries where it is legal, with no “unique and universal” context for its reporting ¹1. Huntington D, Mensch B, Miller VC. Survey questions for the measurement of induced abortion. Stud Fam Plann 1996; 27:155-61.. Due to a condemnatory social norm, women tend to omit the voluntary termination of pregnancy or to declare having miscarried, which results in an underestimation of abortion ²2. Singh S, Remez L, Tartaglione A. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. New York: Guttmacher Institute; 2010.. Where abortion is legal, it is formally recorded at health services, and its occurrence can be directly measured based on official statistics. Nonetheless, legal abortions are recognized as only part of total induced abortions, due to the under-recording and under-reporting of the practice ²2. Singh S, Remez L, Tartaglione A. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. New York: Guttmacher Institute; 2010.^,33. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102..

This becomes considerably worse when the practice is illegal. In these contexts, the clandestine nature and the lack of medical care lead to abortions being carried out under unsafe conditions, that is, provided by unqualified individuals and/or in environments that do not meet minimum health standards ⁴. Under these circumstances, the voluntary interruption of pregnancy may have grave consequences for health, even resulting in death, something that does not happen when the procedure is carried out under safe conditions ⁴4. Organização Mundial da Saúde. Abortamento seguro: orientação técnica e de políticas para sistemas de saúde. Geneva: Organização Mundial da Saúde; 2004.. When abortions are performed clandestinely, there is no possibility of reliable records.

Despite the increased challenges, in very restrictive contexts, research on abortion is indispensable because it enables the estimation of the incidence of abortion and its complications, and the identification of unmet demands and more vulnerable groups, which provides subsidies to health actions and policies.

That is the case of Brazil, where abortion is only permitted in cases of rape, risk to the woman’s life and fetal anencephaly. The criminalization reinforces social inequalities and increases vulnerability to its complications, including death, preferentially affecting women who are black, young, students or domestic workers and who do not have a partner ⁵5. Menezes GMS, Aquino EML. Pesquisa sobre aborto no Brasil: avanços e desafios para o campo da saúde coletiva. Cad Saúde Pública 2009; 25 Suppl 2:S193-204.^,66. Departamento de Ciência e Tecnologia, Secretaria de Ciência, Tecnologia e Insumos Estratégicos, Ministério da Saúde. Aborto e saúde pública no Brasil: 20 anos. Brasília: Ministério da Saúde; 2009. (Série B. Textos Básicos de Saúde)..

In this article, we seek to describe the main methodological challenges of research on abortion in contexts where, like in Brazil, it is illegal, through a review of quantitative original studies on the subject7 and our reflections based on empirical studies we have conducted ⁸8. Aquino EML, Heilborn ML, Knauth D, Bozon M, Almeida MC, Araújo J, et al. Adolescência e reprodução no Brasil: a heterogeneidade dos perfis sociais. Cad Saúde Pública 2003; 19 Suppl 2:S377-88.^,99. Menezes G, Aquino EML, Silva DO. Induced abortion during youth: social inequalities in the outcome of the first pregnancy. Cad Saúde Pública 2006; 22:1431-46.^,1010. Cecatti JG, Guerra GVQL, Sousa MH, Menezes GMS. Aborto no Brasil: um enfoque demográfico. Rev Bras Ginecol Obstet 2010; 32:105-11.^,1111. Aquino EML, Menezes G, Barreto-de-Araújo TV, Alves MT, Alves SV, Almeida MCC, et al. Qualidade da atenção ao aborto no Sistema Único de Saúde do Nordeste brasileiro: o que dizem as mulheres? Ciênc Saúde Colet 2012; 17:1765-76..

The first challenge: obtaining information

The clandestine nature and stigma associated with abortion make its investigation complex, beginning by its very admission by women. The voluntary interruption of pregnancy involves moral, ethical and religious conflicts which, added to social condemnation and reinforced by its illegality, result in its omission or in false reports of miscarriages ¹²12. Singh S, Fetters T, Gebreselassie H, Abdella A, Gebrehiwot Y, Kumbi S, et al. The estimated incidence of induced abortion in Ethiopia, 2008. Int Perspect Sex Reprod Health 2010; 36:16-25.. Thus, simply excluding spontaneous miscarriages from analysis may lead to an underestimation of the incidence of abortion ¹³13. Adler AJ, Filippi V, Thomas SL, Ronsmans C. Incidence of severe acute maternal morbidity associated with abortion: a systematic review. Trop Med Int Health 2012; 17:177-90..

Different strategies and techniques have been used to obtain information with which to estimate the occurrence of abortions, but none completely assures the trustworthiness or completeness of the data.

The most common strategies include using official statistics on legal abortions; demographic surveys on reproductive health (such as the Demographic and Health Surveys that is periodically carried out in many countries), population surveys with representative samples of women, surveys of female health service users and other selected populations, studies of hospital records on admissions due to abortions and studies or mortality from this cause ²2. Singh S, Remez L, Tartaglione A. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. New York: Guttmacher Institute; 2010.^,33. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102.^,1414. Barreto T, Campbell OM, Davies JL, Fauveau V, Filippi VG, Graham WJ, et al. Investigating induced abortion in developing countries: methods and problems. Stud Fam Plann 1992; 23:159-70.. The advantages and limits of each are summarized in Box 1.

The main techniques for producing primary data are extracting data from medical charts and other hospital records and conducting interviews with women using standardized questionnaires, whether face to face or through self-administered instruments, with varying degrees of reporting ²2. Singh S, Remez L, Tartaglione A. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. New York: Guttmacher Institute; 2010.^,33. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102.^,1414. Barreto T, Campbell OM, Davies JL, Fauveau V, Filippi VG, Graham WJ, et al. Investigating induced abortion in developing countries: methods and problems. Stud Fam Plann 1992; 23:159-70..

Self-administered instruments are considered a good alternative because the answers are not known to the person administering the questionnaire and confidentiality is better preserved. However, they largely depend on participants’ educational level and acceptance, though this is not an exclusive limitation of studies on abortion ¹⁵15. Lara D, Strickler J, Olavarrieta CD, Ellertson C. Measuring induced abortion in Mexico: a comparison of four methodologies. Sociol Methods Red 2004; 32:529-58..

Alternatives such as the Randomized Response Technique (RRT) and the Ballot Box Method have been used to increase the accuracy of the information and measure abortion under-reporting ¹⁶16. Medeiros M, Diniz D. Recommendations for abortion surveys using the ballot-box technique. Ciênc Saúde Colet 2012; 17:1721-4.^,1717. Rider RV, Harper PA, Chow LP, I-Cheng C. A comparison of four methods for determining prevalence of induced abortion, Taiwan, 1970-1971. Am J Epidemiol 1976; 103:37-50.. The former is a probabilistic technique used to study stigmatizing or illegal situations, such as abortion, in which the interviewer is completely unaware of the answer; in the latter, the interviewee deposits her answer in a ballot box, using an unidentified ballot with plain language (Figure 1). In Brazil, RRT was used in population surveys in São Paulo State ¹⁸18. Silva RS. O uso da técnica de resposta ao azar (TRA) na caracterização do aborto ilegal. Rev Bras Estud Popul 2014; 10:41-56.^,1919. Silva RS. Especulações sobre o papel do aborto provocado no comportamento reprodutivo das jovens brasileiras. Rev Bras Estud Popul 2002; 19:249-61.; and the Ballot Box Method was used in a study in Rio Grande do Sul ²⁰20. Olinto MTA, Moreira-Filho DC. Fatores de risco e preditores para o aborto induzido: estudo de base populacional. Cad Saúde Pública 2006; 22:365-75. and in the National Abortion Survey (PNA in Portuguese) in 2010 ²¹21. Diniz D, Medeiros M. Aborto no Brasil: uma pesquisa domiciliar com técnica de urna. Ciênc Saúde Colet 2010; 15:959-66. and 2016 ²²22. Diniz D, Medeiros M, Madeiro A. Pesquisa Nacional de Aborto 2016. Ciênc Saúde Colet 2017; 22:653-60..

The construction of culturally-appropriate structured questionnaires, with special care taken with the language and order of questions, may ensure greater acceptance by interviewees and more trustworthy answers ¹1. Huntington D, Mensch B, Miller VC. Survey questions for the measurement of induced abortion. Stud Fam Plann 1996; 27:155-61.. It is essential that researchers avoid questions that cause embarrassment, such as, for example, asking women who probably have had an abortion about the loss of a child. Likewise, researchers should use additional questions which confirm the type of abortion, because technical terms such as miscarriage, induced abortion, therapeutic abortion and voluntary interruption of pregnancy are not self-explanatory and may be difficult for interviewees to understand. In a standardized instrument, the order of questions must be carefully considered in order to avoid the abrupt introduction of the subject and to enable a prior empathy between interviewers and interviewees. The order of questions must be planned so as to make the questionnaire coherent, facilitate event recall, reduce the risk of information loss due to refusal to answer some question or even due to the interruption of the interview. The instrument’s efficiency can be increased by using filters which distinguish different subgroups of experiences. For example, a questionnaire can initially inquire into previous pregnancies, whether or not they were intended, and, next, ask about their outcomes ²³23. Heilborn ML, Aquino EML, Bozon M, Knauth DR, organizadores. Aprendizado da sexualidade: reprodução e trajetórias sociais de jovens brasileiros. Rio de Janeiro: Editora Garamond/Editora Fiocruz; 2006.^,2424. Moreau C, Bajos N, Bouyer J. Question comprehension and recall: the reporting of induced abortions in quantitative surveys on the general population. Population 2004; 59:439-54..

Use of validated instruments - especially for apprehending complex constructs, such as, for example, the quality of post-abortion care - must be ensured in order to enable comparability between studies and the production of trustworthy data ²⁵25. Aquino EML, Menezes GMS, Barreto-de-Araújo TV, Alves MT, Almeida MCC, Alves SV, et al. Avaliação da qualidade da atenção ao aborto: protótipo de questionário para usuárias de serviços de saúde. Cad Saúde Pública 2014; 30:2005-16.^,2626. Aquino EML, Reichenheim M, Menezes GMS, Barreto-de-Araújo TV, Alves MTSSB, Alves SV, et al. Avaliação da qualidade da atenção ao aborto na perspectiva das usuárias: estrutura dimensional do instrumento QualiAborto-Pt. Cad Saúde Pública 2020; 36 Suppl 1:e00197718.^,2727. Rocha BNGA, Uchoa SAC. Avaliação da atenção humanizada ao abortamento: um estudo de avaliabilidade. Physis (Rio J.) 2013; 23:109-27..

Another crucial aspect for the trustworthiness of answers to sensitive questions, such as those regarding abortion and gender violence, consists of the establishment of an appropriate environment that guarantees privacy ²⁸28. Ellsberg M, Heise L, Peña R, Agurto S, Winkvist A. Researching domestic violence against women: methodological and ethical considerations. Stud Fam Plann 2001; 32:1-16.^,2929. Rasch V, Muhammad H, Urassa E, Bergström S. Self-reports of induced abortion: an empathetic setting can improve the quality of data. Am J Public Health 2000; 90:1141-4.^,3030. Schraiber LB, d'Oliveira AFPL, Couto MT. Violência e saúde: contribuições teóricas, metodológicas e éticas de estudos da violência contra a mulher. Cad Saúde Pública 2009; 25 Suppl 2:S205-16.^,3131. Whittaker A. Eliciting qualitative information about induced abortion: lessons from Northeast Thailand. Health Care Women Int 2002; 23:631-41.. A further crucial aspect is the selection of interviewers (preferably women, due to the subject), based on experience, training and age. It is recommended that the selected interviewers not have a stigmatizing stance on abortion.

The need to respect the confidentiality of the information and not to make value judgments during the interview must be emphasized during team training and regular work supervision. In addition to meeting technical standards, interviewers must also be capable of, simultaneously, maintaining the distance needed for scientific production and ensuring support in situations in which practices are revealed, or in which participants are exposed to risks ³⁰30. Schraiber LB, d'Oliveira AFPL, Couto MT. Violência e saúde: contribuições teóricas, metodológicas e éticas de estudos da violência contra a mulher. Cad Saúde Pública 2009; 25 Suppl 2:S205-16.. The team must pay attention to situations in which there is need for psychological support, providing information on reference services.

Primary data on abortion may also be produced through its extraction from medical charts, but the quality depends on the completeness and accuracy of the records, and varies according to the type of document researchers consult. Emergency care records generally present briefer information ³²32. Gilbert EH, Lowenstein SR, Koziol-McLain J, Barta DC, Steiner J. Chart reviews in emergency medicine research: where are the methods? Ann Emerg Med 1996; 27:305-8., and the wealth of details increases as the care becomes more complex, as in the case of Intensive Care Units (ICUs).

Researchers must develop a specific form for data extraction, along with a manual describing its application, so as to guarantee a standardized data collection ³³33. Gregory KE, Radovinsky L. Research strategies that result in optimal data collection from the patient medical record. Appl Nurs Res 2012; 25:108-16.. These instruments, carefully thought-out before the start of field research, must guide team training and supervision. Researchers must consider that records are produced for the purposes of clinical follow-up and are filled out by professionals, with varying degrees of completeness ³³33. Gregory KE, Radovinsky L. Research strategies that result in optimal data collection from the patient medical record. Appl Nurs Res 2012; 25:108-16.. In order to ensure efficiency and the accuracy of the information to be transcribed, the team may be composed of professionals capable of recognizing this type of (often barely legible) writing, as well as the technical terms used, such as, for example, individuals with health-related degrees ³³33. Gregory KE, Radovinsky L. Research strategies that result in optimal data collection from the patient medical record. Appl Nurs Res 2012; 25:108-16.. However, they must strictly follow the research protocol, so as to avoid interpretation biases, and should, preferably, not be aware of the study’s key hypotheses ³³33. Gregory KE, Radovinsky L. Research strategies that result in optimal data collection from the patient medical record. Appl Nurs Res 2012; 25:108-16..

Often, the challenge is the identification of abortion cases itself, which depends on the International Disease Classification code entered into the hospital admission form. In addition to possible failures in this record, the non-standardized use of these codes may harm data compatibility, if studies use different criteria, with greater or lesser specificity. The most recommended course of action is to transcribe data to the form with no interpretations or judgments of the diagnosis, which should be reserved for a later stage, preferably by experts, with blind, standardized double classification.

It may be difficult to distinguish spontaneous miscarriages form induced abortions. One approach used in Brazil ³⁴34. Chaves JHB, Pessini L, Bezerra AFS, Rego G, Nunes R. Abortamento provocado na adolescência sob a perspectiva bioética. Rev Bras Saúde Matern Infant 2010; 10 Suppl 2:S311-9.^,3535. Silva DFO, Bedone AJ, Faúndes A, Fernandes AMS, Moura VGAL. Aborto provocado: redução da frequência e gravidade das complicações - consequência do uso de misoprostol? Rev Bras Saúde Matern Infant 2010; 10:441-7. was proposed by the World Health Organization (WHO) ³⁶36. World Health Organization. Protocol for hospital-based descriptive studies of mortality, morbidity related to induced abortion, WHO Project No. 86912, Task Force on Safety and Efficacy of Fertility Regulating Methods. Geneva: World Health Organization; 1987. based on the work by Figa-Talamanca, which classifies abortions according to the degree of certainty of inducement. The classification of abortions as “certainly induced”, “probably induced”, “possibly induced” and “spontaneous miscarriage” takes into consideration accounts from women, family members and health professionals, in addition to hospital records of abortion-related complications (Box 2). This method has the potential for two types of biases: spontaneous miscarriages with complications and those resulting from unintended pregnancies may be falsely classified as induced; induced abortions with no complications may be categorized as miscarriages. This second type has become particularly relevant in recent decades, due to the increased use of medications such as misoprostol, which are known to reduce severe complications ³3. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102..

The visibility of abortion: strategies for estimating occurrence

Abortion occurrence can be estimated directly (based on primary data) or indirectly (using secondary data), depending on the type of method, as described above. Estimates may further be produced by combining both types of methods ³3. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102..

Population surveys enable researchers to estimate measures which express the occurrence of pregnancies that ended in abortions, health care coverage and demands that are not met by services, but depend on women’s self-reporting, which is subject do the degree of social tolerance of abortion. Therefore, the data obtained always express a minimum level of occurrence ⁸8. Aquino EML, Heilborn ML, Knauth D, Bozon M, Almeida MC, Araújo J, et al. Adolescência e reprodução no Brasil: a heterogeneidade dos perfis sociais. Cad Saúde Pública 2003; 19 Suppl 2:S377-88..

These surveys also have the advantage of identifying women’s profiles, vulnerable groups and abortive itineraries, and including men’s perceptions of their partners’ abortions, in addition to propitiating studies with specific populations (young people, sex workers, women who are HIV positive, among others) ⁸8. Aquino EML, Heilborn ML, Knauth D, Bozon M, Almeida MC, Araújo J, et al. Adolescência e reprodução no Brasil: a heterogeneidade dos perfis sociais. Cad Saúde Pública 2003; 19 Suppl 2:S377-88.^,3737. Madeiro AP, Rufino AC. Aborto induzido entre prostitutas: um levantamento pela técnica de urna em Teresina - PI. Ciênc Saúde Colet 2012; 17:1735-43.^,3838. Villela WV, Barbosa RM, Portella AP, Oliveira LA. Motivos e circunstâncias para o aborto induzido entre mulheres vivendo com HIV no Brasil. Ciênc Saúde Colet 2012; 17:1709-19..

As for indirect estimates for measuring the occurrence of abortion, different methods have been used ³3. Rossier C. Estimating induced abortion rates: a review. Stud Fam Plann 2003; 34:87-102.^,1414. Barreto T, Campbell OM, Davies JL, Fauveau V, Filippi VG, Graham WJ, et al. Investigating induced abortion in developing countries: methods and problems. Stud Fam Plann 1992; 23:159-70., following the proposal of the Alan Guttmacher Institute (AGI) ³⁹39. Alan Guttmacher Institute. Aborto clandestino: uma realidade latino-americana. Nova York: Alan Guttmacher Institute; 1994., which has been applied to several countries. The number of induced abortions is obtained from hospital data, with corrections in the formula for the population estimate, predicting hospital admissions and use of private health services, discounting potential spontaneous miscarriages and adding those which would not lead to a hospitalization. However, the method has limitations which imply a probable overestimation, and is the object of a scientific debate ⁴⁰40. Koch E. Overestimation of induced abortion in Colombia and other Latin American countries. Ginecol Obstet Mex 2012; 80:360-72.^,4141. Singh S, Bankole A. Estimación de la incidencia de aborto inducido: respuesta a la crítica a la metodología del Instituto Guttmacher. Ginecol Obstet Mex 2012; 80:554-61.. Other aspects must be considered with regard to estimate parameters, depending on the context.

For example, in Brazil, estimates using the AGI methodology considered the following as parameters for the correction factor: of the total number of cases, 12.5 % were considered abortions performed outside of the public sector, 25% were considered spontaneous miscarriages, and 25% were considered to require hospitalization due to abortion-related complications ⁴²42. Monteiro MFG, Adesse L, Drezett J. Atualização das estimativas da magnitude do aborto induzido, taxas por mil mulheres e razões por 100 nascimentos vivos do aborto induzido por faixa etária e grandes regiões. Brasil, 1995 a 2013. Reprod Clim 2015; 30:11-8.. However, these values probably vary across the country’s regions. For births, the study Birth in Brazil found that 20% of women used the private sector ⁴³43. Domingues RMSM, Dias MAB, Nakamura-Pereira M, Torres JA, d'Orsi E, Pereira APE, et al. Processo de decisão pelo tipo de parto no Brasil: da preferência inicial das mulheres à via de parto final. Cad Saúde Pública 2014; 30 Suppl:S101-16., in agreement with data from the 2006 National Demographic Survey of Children and Women’s Health⁴⁴44. Centro Brasileiro de Análise e Planejamento, Ministério da Saúde. Pesquisa Nacional de Demografia e Saúde da Criança e da Mulher - PNDS 2006: dimensões do processo reprodutivo e da saúde da criança. Brasília: Ministério da Saúde; 2009. (Série G. Estatística e Informação em Saúde)., which estimated that 27% of the female population was covered by private health insurance, varying from 12% in the Northeast and 37% in the Southeast. Additionally, the PNA showed, in 2010 ²¹21. Diniz D, Medeiros M. Aborto no Brasil: uma pesquisa domiciliar com técnica de urna. Ciênc Saúde Colet 2010; 15:959-66. and 2016 ²²22. Diniz D, Medeiros M, Madeiro A. Pesquisa Nacional de Aborto 2016. Ciênc Saúde Colet 2017; 22:653-60., that 50% of abortions resulted in hospitalizations. Lastly, the proportion of spontaneous miscarriages differs according to women’s age, which would affect the estimates according to age group ⁴⁵45. Ammon Avalos L, Galindo C, Li DK. A systematic review to calculate background miscarriage rates using life table analysis. Birth Defects Res A Clin Mol Teratol 2012; 94:417-23..

Whatever the method used, when estimates are based on hospital records, their interpretation must take into account issues related to the severity of cases and to access to health services. Hospitalizations often express greater severity of cases and the presence of more severe complications, which may even lead to death. Thus, less severe cases tend to be underestimated, because they are resolved without hospitalization. On the other hand, severe cases enable a good estimate of population occurrence, because one may assume that the women only survived because they received hospital care ¹³13. Adler AJ, Filippi V, Thomas SL, Ronsmans C. Incidence of severe acute maternal morbidity associated with abortion: a systematic review. Trop Med Int Health 2012; 17:177-90..

For population estimates, researchers must consider that women with higher levels of income and education have abortions under safer conditions, in private clinics, and therefore are not included in the hospital statistics of the public health systems in Brazil and in other similar contexts. On the other hand, poorer women, who are more exposed to unsafe abortions and are at greater risk for complications, may be over-represented in the indirect estimates, thus reiterating the association between abortion and poverty. However, they are the ones who seek out hospitals, whether to finish emptying the uterus after prior use of misoprostol, or to avoid complications, without this necessarily implying greater severity ⁵5. Menezes GMS, Aquino EML. Pesquisa sobre aborto no Brasil: avanços e desafios para o campo da saúde coletiva. Cad Saúde Pública 2009; 25 Suppl 2:S193-204.^,66. Departamento de Ciência e Tecnologia, Secretaria de Ciência, Tecnologia e Insumos Estratégicos, Ministério da Saúde. Aborto e saúde pública no Brasil: 20 anos. Brasília: Ministério da Saúde; 2009. (Série B. Textos Básicos de Saúde).. On the other hand, those who face discrimination and institutional violence in previous pregnancies, such as black women, may seek out health services less often, and be underestimated in estimates based on hospital statistics ⁴⁶46. Góes EF, Menezes GMS, Almeida MCC, Aquino EML. Vulnerabilidade racial e barreiras individuais de mulheres em busca do primeiro atendimento pós-aborto. Cad Saúde Pública 2020; 36 Suppl 1:e00189618.. Another aspect that deserves attention is hospital re-admissions, which are not very common, but may contribute to the overestimation of the abortion incidence.

Despite the limitations we have discussed, estimates obtained through indirect methods, such as that from the AGI, are justified by the difficulty in obtaining direct estimates in contexts of illegality and, even where abortion is legal and accessible, because of the persistence of unsafe practices resulting from stigma.

When constructing indicators of occurrence, in addition to the aspects related to the “number of abortions” numerator, whatever the chosen measure, other methodological aspects must be discussed. The most commonly used indicators are: abortion rate/1.000 women of fertile age, proportion of pregnancies which result in abortion and ratio of abortions/100 live born children ⁴⁷47. Grimes DA, Benson J, Singh S, Romero M, Ganatra B, Okonofua FE, et al. Unsafe abortion: the preventable pandemic. Lancet 2006; 368:1908-19..

The denominator may be total number of women of fertile age, the total number of pregnant women, or the total number of live born infants. There is also the possibility of using the group of women who have unintended pregnancies. In the first case, the definition of fertile age may vary - 15 to 49 years ⁴⁸48. Fusco CLB, Silva RS, Andreoni S. Unsafe abortion: social determinants and health inequities in a vulnerable population in São Paulo, Brazil. Cad Saúde Pública 2012; 28:709-19.; 15 to 54 years ¹⁰10. Cecatti JG, Guerra GVQL, Sousa MH, Menezes GMS. Aborto no Brasil: um enfoque demográfico. Rev Bras Ginecol Obstet 2010; 32:105-11. - or, due to ethical reasons, only include women who are legal adults22. When investigating young women and adolescents, different age ranges are used - 12 to 19 years ⁴⁹49. Correia DS, Cavalcante JC, Egito EST, Maia EMC. Prática do abortamento entre adolescentes: um estudo em dez escolas de Maceió - AL, Brasil. Ciênc Saúde Colet 2011; 16:2469-76.; 14 to 25 years ⁵⁰50. Silva RS, Andreoni S. Factors associated with induced abortion among poor youth in the city of São Paulo, 2007. Rev Bras Estud Popul 2012; 29:409-19. or 18 to 24 years ⁵¹51. Pilecco FB, Knauth DR, Vigo A. Aborto e coerção sexual: o contexto de vulnerabilidade entre mulheres jovens. Cad Saúde Pública 2011; 27:427-39.. These definitions influence result comparability.

The calculation of the denominator “number of live born infants” may be affected by problems related to information coverage. Consequently, temporal and regional differences may not be exclusively attributed to abortion magnitudes and trends, since both the population of reproductive age and the number of live born infants may change.

A relevant issue is the reference period used, that is, the estimate of induced abortions over the course of the reproductive life ⁵²52. Camargo RS, Santana DS, Cecatti JG, Pacagnella RC, Tedesco RP, Melo Jr. EF, et al. Severe maternal morbidity and factors associated with the occurrence of abortion in Brazil. Int J Gynaecol Obstet 2011; 112:88-92. or within a specific period - over the previous five years ⁵³53. Camargo RS, Pacagnella RC, Cecatti JG, Parpinelli MA, Souza JP, Sousa MH. Subsequent reproductive outcome in women who have experienced a potentially life-threatening condition or a maternal near-miss during pregnancy. Clinics 2011; 66:1367-72. or the previous year ²²22. Diniz D, Medeiros M, Madeiro A. Pesquisa Nacional de Aborto 2016. Ciênc Saúde Colet 2017; 22:653-60.. Studies which use “lifetime” as the reference period usually find higher values because it is a cumulative experience in a greater period of exposure to unplanned pregnancies. They may also be affected by recall bias, with the tendency toward remembering the more recent and/or more significant events (for example, those that had complications or demanded hospitalization).

Investigation of factors associated with induced abortion

In a review of articles on unsafe abortion in Brazil ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418., among the quantitative studies published between 2008 and 2018, most were cross-sectional, with the limitation of ensuring the temporal sequence of events. Many used small samples and, despite good methodological quality, the generalizability of their findings was limited because they referred to very specific contexts. Works with greater sample sizes had deficiencies in their statistical analysis and few studies reported statistical power, not including, for example, confidence intervals for their estimates of abortion prevalence. Many of the studies relied on participant accounts, obtained through interviews, to measure independent variables and induced abortion, with no validation from a different source of information ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418.. Another important aspect is that many determinants were often measured using the moment of the interview as the reference, instead of the period when the abortion took place, further worsening the issue of temporality. For example, martial status, income, number of children, contraceptive use are aspects that vary over women’s lives. This leads some results to be clearly biased, with a greater prevalence of abortion among women with tubal ligation, who are no longer able to become pregnant, or the reverse causality between women with no children and abortion.

Many of the studies on determinants of abortion and its complications did not clearly present the conceptual models used when analyzing associations, or used inadequate models ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418.. The choice of variables, in general, was not justified and, in some cases, was inappropriate. Another aspect related to conceptual models is the comparison between male accounts of their partners’ abortions and the accounts directly provided by women. Although the focus on male participation in abortion is laudable, results from this type of comparison must be interpreted with caution, taking into consideration gender differences both in the experiences and the accounts thereof.

In addition, the choice of comparison groups for the outcome “induced abortion” was very varied and subject to biases. For example, comparing induced abortions with spontaneous miscarriages may lead to an underestimation of risk factors, because the group of women who reported spontaneous miscarriages may include some who had induced abortions, but did not report them. Additionally, induced events occur more frequently among women with unintended pregnancies. This group should be the population base, both in cohort and case-control studies ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418..

Estimates of the occurrence of complications associated with abortions

A data source that is traditionally used to study complications from abortions are mortality statistics, which express the most serious side of the problem.

Use of mortality data from any cause has limitations related to the system’s coverage and the quality of information recorded in Death Certificates (DC) ⁵⁴54. Laurenti R, Jorge MHPM, Gotlieb SLD. A mortalidade materna nas capitais brasileiras: algumas características e estimativa de um fator de ajuste. Rev Bras Epidemiol 2004; 7:449-60.. Maternal deaths are known to be especially affected by under-reporting, which led, in Brazil, to a series of initiatives, from including a field for identifying pregnancy in DC to the investigation of maternal deaths, which was officially made an attribution of the epidemiological surveillance system ⁵⁵55. Departamento de Análise de Situação em Saúde, Secretaria de Vigilância em Saúde, Ministério da Saúde. Guia de vigilância epidemiológica do óbito materno. Brasília. Ministério da Saúde; 2009. (Série A. Normas e Manuais Técnicos).. Consequently, calculations of maternal mortality measures depend on the proportion of deaths of women of fertile age that have been investigated, the confirmation of causes of death as maternal, and the incorporation of new cases into the official information system.

However, abortion is considered one of the most poorly-reported causes of maternal mortality ⁴⁷47. Grimes DA, Benson J, Singh S, Romero M, Ganatra B, Okonofua FE, et al. Unsafe abortion: the preventable pandemic. Lancet 2006; 368:1908-19., and there are differences depending on whether one uses the immediate cause or contributing causes of death when calculating the maternal mortality ratio (MMR). Recent studies have estimated a 30-40% increase in MMR when multiple causes are used ⁵⁶56. Cardoso B, Vieira F, Saraceni V. Aborto no Brasil: o que dizem os dados oficiais? Cad Saúde Pública 2020; 36 Suppl 1:e00188718.^,5757. Martins EF, Almeida PFB, Paixão CO, Bicalho PG, Errico LSP. Causas múltiplas de mortalidade materna relacionada ao aborto no Estado de Minas Gerais, Brasil, 2000-2011. Cad Saúde Pública 2017; 33:e00133115.. Considering the illegality of the practice, it is possible that delays in receiving care and complications that result in death after 42 days (delayed death) facilitate its omission as an immediate cause in the DC, favoring under-reporting of abortion as a cause of maternal mortality. Additionally, violent causes of death, such as homicide and suicide, which are potentially related to pregnancy, may be under-reported, since they do not compose the numerator when calculating MMR ⁵⁸58. Alves MMR, Alves SV, Antunes MBC, Santos DLP. Causas externas e mortalidade materna: proposta de classificação. Rev Saúde Pública 2013; 47:283-91..

Starting in the 2000s, in the international literature, there has been a rise of investigations that analyze cases of women who developed severe morbid conditions due to maternal causes and, among them, more severe cases - the so-called near misses ⁵⁹59. Geller SE, Rosenberg D, Cox SM, Kilpatrick S. Defining a conceptual framework for near-miss maternal morbidity. J Am Med Womens Assoc 2002; 57:135-9..

Complications from induced abortions encompass a broad spectrum of conditions. Studies on maternal morbidity have used a typology of complications (Figure 2) which ranges from less severe cases, conditions that are potentially not life-threatening, more severe situations, which are potentially life-threatening, up to near misses, defined as those in which the woman almost died, but survived severe complications during the pregnancy-delivery period - and death ⁶⁰60. Say L, Souza JP, Pattinson RC. Maternal near miss-towards a standard tool for monitoring quality of maternal health care. Best Pract Res Clin Obstet Gynaecol 2009; 23:287-96.^,6161. Souza JP, Cecatti JG, Haddad SM, Parpinelli MA, Costa ML, Katz L, et al. Correction: the WHO maternal near-miss approach and the Maternal Severity Index Model (MSI): tools for assessing the management of severe maternal morbidity. PLoS One 2013; 7(8)..

Initial studies on maternal near misses had different criteria for classifying cases, which limited result comparability. In 2009, the WHO proposed a classification typology. This line of research with standardized criteria has been considered an advancement, because it enables the evaluation of the quality of obstetric care, comparing services, monitoring and epidemiological surveillance. It also leads to greater operational ease due to the greater possibility of obtaining data, since morbid cases are comparatively more frequent than deaths, in addition to information being obtained directly from women ⁵⁹59. Geller SE, Rosenberg D, Cox SM, Kilpatrick S. Defining a conceptual framework for near-miss maternal morbidity. J Am Med Womens Assoc 2002; 57:135-9.^,6262. Geller SE, Rosenberg D, Cox S, Brown M, Simonson L, Kilpatrick S. A scoring system identified near-miss maternal morbidity during pregnancy. J Clin Epidemiol 2004; 57:716-20.. However, applying this model may be difficult in certain contexts, such as the Brazilian one, because it requires records on clinical condition, laboratory alterations and how cases are handled in health services ⁶³63. Witteveen T, Bezstarosti H, de Koning I, Nelissen E, Bloemenkamp KW, van Roosmalen J, et al. Validating the WHO maternal near miss tool: comparing high-and low-resource settings. BMC Pregnancy Childbirth 2017; 17:194..

In Brazil, studies have examined mortality from abortion, however, studies on morbidity due to this cause have only recently used the typology that includes severe maternal morbidity and near miss ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418..

Complications and deaths associated with abortion may also be investigated through interviews and by extracting data from hospital charts ⁵³53. Camargo RS, Pacagnella RC, Cecatti JG, Parpinelli MA, Souza JP, Sousa MH. Subsequent reproductive outcome in women who have experienced a potentially life-threatening condition or a maternal near-miss during pregnancy. Clinics 2011; 66:1367-72. or through secondary data available on information systems ⁶⁴64. Santana DS, Cecatti JG, Parpinelli MA, Haddad SM, Costa ML, Sousa MH, et al. Severe maternal morbidity due to abortion prospectively identified in a surveillance network in Brazil. Int J Gynaecol Obstet 2012; 119:44-8.^,6565. Singh S, Monteiro MF, Levin J. Trends in hospitalization for abortion-related complications in Brazil, 1992-2009: why the decline in numbers and severity? Int J Gynaecol Obstet 2012; 118 Suppl 2:S99-106..

Data obtained from interviews are subject to recall bias and, in the case of morbidity, accuracy is strongly related to the type of event. In a validation study of a questionnaire for maternal near miss ⁶⁶66. Souza JP, Cecatti JG, Pacagnella RC, Giavarotti TM, Parpinelli MA, Camargo RS, et al. Development and validation of a questionnaire to identify severe maternal morbidity in epidemiological surveys. Reprod Health 2010; 7:16., researchers found that recall of previous hysterectomy had the highest trustworthiness ratio, followed by admission to an ICU, blood transfusion, eclampsia with or without convulsions. Hemorrhage and puerperal infections had much lower values. The use of standardized questionnaires already used in national studies ⁶¹61. Souza JP, Cecatti JG, Haddad SM, Parpinelli MA, Costa ML, Katz L, et al. Correction: the WHO maternal near-miss approach and the Maternal Severity Index Model (MSI): tools for assessing the management of severe maternal morbidity. PLoS One 2013; 7(8). is thus reinforced for identifying cases of maternal near miss in population surveys, which would facilitate study comparability.

Final thoughts

Due to all of the reasons listed here, it is clear that abortion and its complications are difficult to measure, imposing countless methodological challenges. These are joined by ethical challenges - especially the need to preserve data secrecy and confidentiality, as well as the safety of the research team and, above all, of the interviewed women, who may be reported to law enforcement even by the health care workers who treat them ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418.^,6767. Diniz D, Corrêa M, Squinca F, Braga KS. Aborto: 20 anos de pesquisas no Brasil. Cad Saúde Pública 2009; 25:939-42.^,6868. Diniz D, Madeiro A. Cytotec e aborto: a polícia, os vendedores e as mulheres. Ciênc Saúde Colet 2012; 17:1795-804.. Likewise, we must consider potential risks from a psychological standpoint, when calling upon women to speak of something that is emotionally mobilizing, especially considering that some of the studies are carried out while they are still in the hospital. Attention and care in the interaction imply taking in emotions, creating empathy with interviewees and, if necessary, referring them to follow-up by a mental health professional. Research on abortion must, therefore, consider that methodological decisions have reciprocal implications with ethical decisions.

More robust theoretical models are needed for investigating induced abortion ⁷7. Domingues RMSM, Fonseca SC, Aquino EML, Menezes GMS. Aborto inseguro no Brasil: revisão sistemática da produção científica 2008-2018. Cad Saúde Pública 2020; 36 Suppl 1:e00190418.. We must likewise overcome gaps, especially regarding service quality and their effects on complications and death due to abortion. New methods for obtaining incidence data have been developed and applied in many countries ²2. Singh S, Remez L, Tartaglione A. Methodologies for estimating abortion incidence and abortion-related morbidity: a review. New York: Guttmacher Institute; 2010., however, we must redouble efforts to investigate complications and deaths due to abortion ⁶⁹69. Gerdts C, Tunçalp O, Johnston H, Ganatra B. Measuring abortion-related mortality: challenges and opportunities. Reprod Health 2015; 12:87. and the role of stigma and discrimination in health services in determining them.

Especially in countries where abortion is criminalized, such as Brazil, studies must be carried out so as to determine the dimension of the morbi-mortality resulting from unsafe practices, since they affect young, black and poor women in particular, in a clearly avoidable manner.

In order to overcome some of the challenges we identified, we require investments in research that subsidize the development and perfecting of the methodological aspects of abortion studies, with an emphasis on the development of theoretical models, definition of study population, improvement of measurements of induced abortions and associated factors.

Among current issues that must be investigated are changes in abortion strategies employed in restrictive legal contexts. In countries where abortion is legal, medication abortions are offered under the supervision of health professionals. However, in contexts where abortion is criminalized, women, especially those who are younger, have used self-abortion strategies, turning to online services, which offer direct lines of information on medications ⁷⁰70. Kapp N, Blanchard K, Coast E, Ganatra B, Harries J, Footman K, et al. Developing a forward-looking agenda and methodologies for research of self-use of medical abortion. Contraception 2018; 97:184-8..

The scientific production must provide a basis for public policies and, for this, we must invest in comparative studies of different regions of the country - multicentric, population studies - with the inclusion of women from rural areas and smaller towns, as well as indigenous women, quilombolas, women with disabilities, among other groups that are more vulnerable to social exclusion. The combination of multi-disciplinary strategies is a requirement in these studies, since abortion is a complex phenomenon and must be addressed from different perspectives so as to be understood.

Acknowledgments

We thank the partners from the research teams that investigate the subject, with whom we share the challenges discussed in the article. Estela M. Aquino is a recipient of a 1D productivity grant from CNPq.

References

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