Incidence and recurrence of common mental disorders after abortion: Results from a prospective cohort study
Introduction
Over the last decade, a number of reviews on mental health consequences of abortion have been conducted (APA, 2008, Charles et al., 2008, Robinson et al., 2009, Steinberg and Russo, 2009, National Collaborating Centre for Mental Health (NCCMH), 2011, Coleman, 2011). These reviews showed that the field is severely hampered by methodological problems. With the exception of one review (Coleman, 2011), which has been critically refuted (e.g., Abel et al., 2012, Polis et al., 2012, Steinberg et al., 2012), all concluded that the highest quality empirical research so far has found no evidence that abortion increases the risk on mental disorders. As experiments would be unethical in this field, all claims are based on observational research. Even though some of these studies make use of carefully chosen reference groups and rigorously adjust for covariates, the methodological literature shows that other strategies, like matching, could offer additional insight (Kessler and Schatzberg, 2012), especially in situations in which standard regression methods perform poorly due to insufficient overlap in covariate distributions (Stuart, 2010, Rosenbaum and Rubin, 1983, Cook et al., 2008, Iacus et al., 2012). In the current study, we chose to use a prospective cohort design with 1-to-1 matching, to address a number of the most commonly mentioned methodological problems in this area of research.
One methodological problem in this field is that pre-existing mental health problems are inadequately measured, even though it is likely that these are predictive of post-abortion mental disorders (Gilchrist et al., 1995, Major et al., 2000). Former studies have shown that lifetime psychiatric disorders are highly prevalent among women having abortions (Van Ditzhuijzen et al., 2013, Steinberg et al., 2014), which could lead to incorrect attribution of these disorders to the abortion. Several studies have adjusted for pre-existing mental disorders, but in these studies abortion history was assessed through retrospective self-report (Mota et al., 2010, Fergusson et al., 2009, Steinberg and Finer, 2011, Steinberg et al., 2014), so that the order of abortion and mental disorder cannot be ascertained accurately (Charles et al., 2008, APA, 2008, Major et al., 2009, National Collaborating Centre for Mental Health (NCCMH), 2011). Other studies measured abortion history prospectively and controlled for pre-existing mental disorders, but these measured only a few disorders (Major et al., 2000, Biggs et al., 2015), or previous mental disorders were assessed by family doctors (Gilchrist et al., 1995) or based on psychiatric contact (Munk-Olsen et al., 2011), which could lead to serious underreporting of mental disorders. These findings should therefore be complemented with research using a strong structured diagnostic instrument to assess a wide variety of clinical-level mental disorders, hereby taking into account the onset of these disorders in order to determine whether disorders were already present before the pregnancy was terminated. The current study fills this gap.
A second serious threat to validity in this type of research is confounding by covariates (APA, 2008; NCCMH, 2011). Since it is impossible to randomly assign women to an abortion or control condition, and there is no rigorous way to guarantee comparability between groups (Kessler and Schatzberg, 2012), alternative methods to regression adjustment could offer additional insight. One of the techniques that is strongly recommended in the methodological literature is matching, which allow one to analyze a non-experimental study so that it mimics characteristics of an experiment, because the distribution of baseline covariates is similar between groups (Austin, 2011). In the current study, we matched participants 1-to-1 on confounding covariates. This type of matching induces balance in the distributions of the measured covariates between the two cohorts, and simulation studies have also shown that it can reduce imbalance in unmeasured covariates considerably (Cook et al., 2008, Stuart, 2010, Stürmer et al., 2010).
A third methodological issue which has repeatedly been mentioned by review studies (e.g., APA, 2008, National Collaborating Centre for Mental Health (NCCMH), 2011), is the use of inappropriate reference groups, such as women who never had been pregnant, miscarried, or delivered a (presumably intended) pregnancy. The choice of reference group is dependent on the type of causal question (Charles et al., 2008). In this area of research, two different types of causal questions are often confused (Fergusson et al., 2009, Kessler and Schatzberg, 2012). The first question is whether abortion of an unwanted pregnancy has more, or less, adverse effects on mental health than its realistic alternatives (such as carrying the unwanted pregnancy to term). This question has recently been investigated by the Turnaway Study (e.g., Foster et al., 2015, Biggs et al., 2015, Rocca et al., 2013), using a reference group of women whose abortion requests were declined. This is an adequate design to investigate effects of abortion versus being denied an abortion, when the unwanted pregnancy is a given. The second question is whether the life event of termination of an unwanted pregnancy increases the risk on mental disorders. It is this question that is being addressed in the current study. In this study design, measures based on before-after intra-person comparisons are compared between groups which are matched on confounding covariates. This design provides information about the consequences of the whole life event, which is lost when focusing on the specific effect of abortion versus denial of abortion.
The main goal of this study is to investigate the incidence and recurrence of mental disorders after termination of an unwanted pregnancy. The research question is whether having an abortion of an unwanted pregnancy is associated with an increased risk for the development of (1) incident and (2) recurrent mental disorders at follow-up (2.5–3 years later). We matched women who had an abortion of an unwanted pregnancy 1-to-1 on confounding covariates to women from the general population who did not have an abortion.
Section snippets
Study design
The Dutch Abortion and Mental Health Study (DAMHS) was developed in close cooperation with the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2; De Graaf et al., 2010a, De Graaf et al., 2010b, De Graaf et al., 2012), therefore all outcome variables and covariates were measured in the exact same way. The reference cohort was taken from NEMESIS-2. All pregnancies in the abortion group were unwanted, therefore the term abortion also includes the unwanted pregnancy here. The study
Descriptives
Descriptives of the DAMHS and the reference cohort at T0 are displayed in Table 1. The women in the abortion cohort were overall younger, more often single, without children, of non-western ethnicity, non-religious, unemployed, living in urban areas, and more often had experienced childhood abuse, than women in the reference cohort. There were no significant differences for level of education. After matching, balance was induced on the variables that were used for the matching. Even though
Discussion
After 2.5–3 years post-abortion, we initially found differences in incidence of mental disorders in our unmatched and unadjusted data, but matching strongly attenuated the results by decreasing differences between the two cohorts. This implies that the initial differences in incidence of disorders in the 2.7 year period after the abortion, cannot be attributed to the event of the abortion (including the unwanted pregnancy); rather, they seem to be largely dependent on co-occurring variations in
Contributors
Authors Vollebergh and Van Nijnatten designed the study, in cooperation with authors De Graaf and Ten Have. Author Van Ditzhuijzen managed the literature searches, data collection and analysis, supervised by author Ten Have. Author Lugtig supervised analyses and wrote part of the content related to the coarsened exact matching. Author Van Ditzhuijzen wrote the first draft of the manuscript. All authors contributed to and have approved the final manuscript.
Funding sources
This work was supported by the Dutch Ministry of Health, Welfare and Sport, via the Netherlands Organisation for Health Research and Development (ZonMW, grant number 127000003).
Conflicts of interest
None.
Acknowledgements
We thank Saskia van Dorsselaer for the management of the data cleaning according to NEMESIS-2 standards, and data analysis advice.
References (49)
- et al.
Abortion and long-term mental health outcomes: a systematic review of the evidence
Contraception
(2008) - et al.
First-incidence of DSM-IV mood, anxiety and substance use disorders and its determinants: results from The Netherlands mental health survey and incidence study-2
J. Affect. Disord.
(2013) - et al.
Commentary on abortion studies of Steinberg and finer (social science & medicine 2011;72:72-82) and coleman (journal of psychiatric research 2009;43:770-6 & journal of psychiatric research 2011;45:1133-4)
J. Psychiat. Res.
(2012) - et al.
Does mood-congruence or causal search govern recall bias? A test of life event recall
J. Clin. Epidemiol.
(1994) - et al.
Evaluating research on abortion and mental health
Contraception
(2009) - et al.
Examining the association of abortion history and current mental health: a reanalysis of the National Comorbidity Survey using a common-risk-factors model
Soc. Sci. Med.
(2011) - et al.
Fatal flaws in a recent meta-analysis on abortion and mental health
Contraception
(2012) - et al.
Childhood adversities and subsequent risk of one or multiple abortions
Soc. Sci. Med.
(2013) - et al.
Psychiatric history of women who have had an abortion
J. Psychiat. Res.
(2013) - et al.
The impact of psychiatric history on women's pre- and postabortion experiences
Contraception
(2015)
Abortion and mental health: guidelines for proper scientific conduct ignored
Br. J. Psychiat.
Sampling and methods of the European study of the epidemiology of mental disorders (ESEMeD) project
Acta Psychiat. Scand. Suppl.
Diagnostic and Statistical Manual of Mental Disorders
Report of the APA Task Force on Mental Health and Abortion
An introduction to propensity score methods for reducing the effects of confounding in observational studies
Multivar. Behav. Res.
Mental health diagnoses 3 years after receiving or being denied an abortion in the United States
Am. J. Public Health
Abortion and mental health: quantitative synthesis and analysis of research published 1995-2009
Br. J. Psychiat.
Three conditions under which experiments and observational studies produce comparable causal estimates: New findings from within-study comparisons
J. Policy Anal. Manag.
Temporal sequencing of lifetime mood disorders in relation to comorbid anxiety and substance use disorders
Soc. Psych. Psych. Epid.
The Netherlands mental health Survey and incidence Study-2 (NEMESIS-2): design and methods
Int. J. Meth. Psychiat. Res.
De psychische gezondheid van de Nederlandse bevolking. NEMESIS-2: Opzet en eerste resultaten
Prevalence of mental disorders and trends from 1996 to 2009. Results from The Netherlands mental health Survey and incidence Study-2
Soc. Psychiatry Psychiat. Epidemiol.
Propensity score-matching methods for nonexperimental causal studies
Rev. Econ. Stat.
Reactions to abortion and subsequent mental health
Br. J. Psychiat.
Cited by (17)
The association between first abortion and first-time non-fatal suicide attempt: a longitudinal cohort study of Danish population registries
2019, The Lancet PsychiatryCitation Excerpt :Additionally, we did not examine recurrent suicide attempts or suicide attempts around more than one abortion. Other studies regarding abortion and mental health have examined recurrent mental health problems separately from incident ones;33,35,36 and others contend that recurrent suicide attempts or mental health problems are distinct from incident or new suicide attempts or mental health problems.37–39 Researchers also contend that having more than one abortion is distinct from having a first abortion.40
Long-term incidence and recurrence of common mental disorders after abortion. A Dutch prospective cohort study
2018, Journal of Psychiatric ResearchCitation Excerpt :The current study aims to fill this gap. In an earlier case-controlled cohort study, we found that abortion was not associated with higher incidence of disorders in the 2.5–3 years post-abortion, but women who had an abortion seemed at slightly increased risk for recurrence of any mental disorder (Van Ditzhuijzen et al., 2017). In the current study, we investigated whether these results hold in the long term.
Voluntary Interruption of Pregnancy in Colombia: Contributions to the Debate from Public Mental Health
2018, Revista Colombiana de PsiquiatriaDepression and associated psychosocial factors following a legal abortion in Mexico
2023, Revista Latinoamericana de PsicologiaReflections on abortion rights: From policy to medicine
2022, BioScience Trends