Despite such claims, no study has yet examined whether long-term mental health problems for women following UPA differ from those following WPA. The present study aims to amend this defect in the literature. The question has important implications for policy since, if the APA is correct that WPAs are more psychologically harmful, neglect of them may lead to the systematic understatement of mental health problems following abortion. The hypothesis of this study is that, compared to the corresponding births, WPAs will be associated with greater mental health risk than UPAs. Designed to address all of the above-noted methodological concerns, the present study examines the risk of seven clinical disorders, defined by Diagnostic and Statistical Manual, Version 4, American Psychiatric Association (DSM-IV) or other well-validated criteria, for women exposed to WPA compared to those exposed to UPA, relative to corresponding births, in a nationally representative cohort of ever-pregnant U.S. women assessed at three points over thirteen years.

Reviews by American and British medical associations have asserted that abortion is not psychologically harmful, but only with respect to unwanted or unplanned pregnancies. The APA Task Force found, for example, that “among adult women who have anthe relative risk of mental health problems is no greater if they have a single elective first-trimester abortion than if they deliver that pregnancy (emphasis in original)” [ 4 ]. The U.S. National Academy of Sciences (NAS) reached a similar conclusion when examining “whether women who have an abortion experience more mental health problems than women who deliver an(emphasis added)” [ 9 ], as did Great Britain’s Academy of Medical Royal Colleges (AMRC) on the question posed as follows: “Are mental health problems more common in women who have an induced abortion, when compared with women who deliver an(emphasis added)” [ 6 ]?

A series of recent studies based on clinical samples of women not permitted to finalize a desired abortion for medical or legal reasons, known as the Turnaway Study [ 23 25 ], has claimed to provide strong evidence of minimal mental health disorders [ 9 ]. However, this study design cannot examine the crucial difference in outcomes between women who choose to terminate a pregnancy by abortion and those who do not. The Discussion section addresses this issue further.

Recent research has focused on overcoming the limitations of retrospective cross-sectional fertility data in favor of rigorous longitudinal designs which can more clearly establish the time order of cause and effect [ 4 18 ]. Most studies using longitudinal data, however, have only analyzed reported outcomes at terminus, which does not make full use of the potential of the data to model temporal sequence [ 17 45 ]. Such studies have also been limited by short follow-up periods following abortion, from as little as one month [ 46 ] to no more than five years [ 23 47 ]. Some of the strongest evidence to date has come from three longitudinal studies by Fergusson, Pedersen, and Sullins of women in New Zealand, Norway, and the United States that measured health outcomes and abortion status over at least three points in time from adolescence into the late 20s. All three studies found significant post-abortion increases in the risk of affective and addictive disorders, including depression, thoughts of suicide, anxiety, and abuse of illicit drugs, marijuana, or alcohol [ 20 49 ].

The literature on abortion and mental health is sharply divided between studies finding psychological risks following abortion to be significant and persistent [ 15 22 ] and those finding them to be negligibly small and transient [ 23 28 ]. Some studies have found a positive association between having an abortion and a range of difficulties [ 17 30 ] including suicidality [ 18 19 ], depression [ 15 33 ], anxiety [ 15 34 ], and substance abuse [ 19 35 ]. Other studies have reported weak or null results on all these outcomes [ 23 37 ]. Competing reviews have vigorously critiqued the methodology of those on the other side of the divide [ 6 29 ], (for reviews of the entire controversy see [ 30 41 ]). The controversy has prompted successive methodological improvements, including insistence on population representative data, comparison samples, validated measures of mental disorder, substantial controls for prior medical history, confounding covariates and alternate pregnancy outcomes, and a preference for longitudinal cohort data with long term (at least 7 years) follow up [ 25 42 ].

Retrospectively assessed wantedness may manifest at the time of the procedure as ambivalence or being conflicted with the intentions of others. In abortion clinic intake surveys 14–24% of patients indicated that she was acceding to the wishes of her partner, 6–8% to the wishes of her parents, and 8–12% reported health problems as one reason among others for the abortion [ 10 ]. More detailed studies of decision-making among women seeking abortions have found that 10% of minor women and 3% of adult women indicated that they sought an abortion primarily because of pressure from others [ 12 ], 8% scored high on a measure of “decisional conflict”, and 5% indicated that they “preferred to have the baby” [ 13 ]. Research in the National Survey of Family Growth (NSFG) also suggests that discordant partner intentions may influence the abortion of a first pregnancy otherwise intended by the woman [ 14 ].

Recent research has supported the APA Task Force’s speculation that abortions of wanted pregnancies may be “associated with more negative psychological reactions among women who have had an abortion” [ 4 ]. Intake studies of women seeking an abortion have found that feeling pressured by others and low confidence in the abortion decision increased the risk of poor post-abortion coping [ 10 ]. Rocca et al. found that women aborting planned pregnancies had lower odds of reporting that the abortion was the right decision and had more negative emotional reactions immediately following the abortion [ 11 ].

The proportion of women obtaining WPAs is small compared to abortions of unwanted pregnancies (hereafter “UPA”) [ 5 6 ], but it is not trivial. Finer reports that 8% of pregnancies ending in abortion were reported as intended on the 2002 National Survey of Family Growth (NSFG) [ 7 ]. In the U.S. cohort examined for the present study, 14.7% of total abortions, involving 18.3% (95% CI 16–21) of ever-aborting women, were of pregnancies reported as wanted. Data on the reasons for such abortions are not available. The Task Force on Mental Health and Abortion of the American Psychological Association (APA) has speculated that “[w]omen who terminate wanted pregnancies typically do so because of fetal anomalies or risks to their own health” [ 5 ]. No doubt this accounts for a portion of such terminations, however, life-threatening fetal anomalies occur at only about one-tenth the rate of WPA. In the Add Health data, 51 of every thousand pregnancies reported by women ended in a wanted pregnancy abortion, but major cardiac deformity, the most common neonatal abnormality, only occurs in about four of 1000 births, and the most common fetal screening procedure, an ultrasound at 18–23 weeks, is not more than 60% successful in identifying such abnormalities [ 8 ]. Even by the most generous estimate, and counterfactually assuming no abortion concealment, no more than a fifth of the reported wanted child abortions could be due to fetal abnormalities. Although more frequent debilitating anomalies such as Down Syndrome or Trisomy 13 are also increasingly indications for abortion. Whatever the rate, the U.S. National Academy of Science’s 2018 Report on abortion care advises: “Terminations of pregnancies due to fetal abnormalities may have very different psychological consequences than abortions for unwanted pregnancies” [ 9 ].

Each year almost seven million induced abortions terminate pregnancies which the patient later assesses to have been planned or wanted. This estimate interpolates the rate of wanted pregnancy abortions found in this study (14.7%) to the estimated 56 million global abortions per year 2010–2014 reported by World Health Organization surveillance [ 1 2 ], reduced by 15% to ensure a conservative estimate. The resulting number is 6,997,200 annual abortions of wanted pregnancies. Although such wanted pregnancy abortions (hereafter “WPA”) are thought to be more psychologically distressing [ 3 4 ], long-term psychological outcomes following such abortions have not previously been studied.

Relative risk ratios (RRs) for each association of abortion by pregnancy intention with mental disorder were computed using population-averaged longitudinal logistic regression models. Incidence rate ratios (IRRs) for the number of affective disorders, substance abuse disorders and total number of mental disorders were estimated from the corresponding poisson models. The RRs and IRRs are interpreted as the ratio of the probability of experiencing the indicated psychological outcome (for example, depression) conditional on being in each state of the independent variable (for example, WPA), averaged (or pooled) over all time periods. Also computed were the corresponding odds ratios (OR), that is, the ratio of the odds of experiencing the indicated psychological outcome (for example, depression) for those in the indicated state (for example, WPA) compared to the odds of experiencing the outcome for those not in the indicated state. Model fit was assessed using the Archer–Hosmer–Lemeshow F-adjusted mean residual test [ 53 ]. Analyses were performed with Stata 13 statistical software, incorporating the design features of the survey following published guidelines [ 54 ]. RRs computed from random effects and fixed effects models were very similar (not shown).

The unit of analysis was not simply pregnancy intention or outcome, but women who had experienced the pregnancy outcome-by-intention combinations of interest. Accordingly, the analysis examined four design conditions: (1) ever-aborting women who had aborted only unwanted pregnancies (unwanted pregnancy abortion (UPA); Wave IV n = 807); (2) women ever giving birth who had brought to term one or more unwanted pregnancies (unwanted pregnancy birth (UPB); Wave IV n = 1913); (3) women ever giving birth who had brought only wanted pregnancies to term (wanted pregnancy birth (WPB); Wave IV n = 1345); and (4) ever-aborting women who had aborted one or more wanted pregnancies (wanted pregnancy abortion (WPA); Wave IV n = 210). The conditions were not mutually exclusive. Conditions 1 and 2 were compared to determine the effect of abortion relative to birth for unwanted pregnancies; conditions 3 and 4 were compared to determine the effect of abortion relative to birth for wanted pregnancies.

Other covariates fitted included retrospective measures of childhood family conditions, including poverty status, parental education, and any physical, sexual or verbal abuse; conditions measured at baseline, including neuroticism, conduct problems, community integration, and school grade point average; conditions measured at terminus, including educational attainment, current relationship satisfaction, and lifetime rape victimization; and time-dynamic covariates measured at all three Waves, including income, marital status, and intimate partner violence (IPV) victimization. Detailed descriptions of these measures have been previously published [ 49 ].

To better isolate the effect of abortion, the analysis adjusted for multiple covariates that were significantly associated with prior or current mental distress or the precipitation of unwanted pregnancy. To fully adjust for prior mental health history, all seven outcomes were entered as continuous measures at Wave I, and lagged values of all outcomes at any prior waves, that is, at Wave I for Wave III measures, and at Waves I and III for Wave IV measures, were entered as covariates at every wave.

Measures of pregnancy outcomes and intentions were compiled from retrospective accounts at each Wave. Pregnancies ending in miscarriage, stillbirth, ectopic pregnancy, or other pregnancy loss were combined into a single category of “involuntary pregnancy loss”, resulting in pregnancy outcome categories of birth, abortion, and involuntary pregnancy loss. For each pregnancy, respondents were asked to respond yes or no to the question: “Thinking back to the time just before this pregnancy with {initials}, did you want to have a child then?” Women responding “yes” for any aborted pregnancy were coded as having experienced WPA, yielding analysis categories of never abortion, UPA only, and ever WPA. The corresponding procedure for births yielded categories of never birth, wanted pregnancy births (WPB) only, and ever unwanted pregnancy birth (UPB). A woman could thus be in both birth and abortion categories for a given comparison, which accurately reflects the complex interaction of abortions and births in women’s pregnancy decisions over time.

To assess psychological outcomes, the present study included opioid abuse in addition to the previously-described outcomes of depression, anxiety disorder, suicidal ideation, illicit drug abuse, cannabis abuse and alcohol abuse. Opioid abuse was measured at Wave I by a general question that included using “pills…without a doctor’s prescription”, and at Waves III and IV by more detailed questions that asked about the use of pain killers or opioids, naming four to six common brands such as Vicodin or Percodan, either without a prescription or “in larger amounts than prescribed, more often than prescribed, for longer periods than prescribed, or that you took only for the feeling or experience they caused?”

The present study examined seven mental health and substance abuse outcomes, imposing five demographic controls and 20 covariates. The variables are listed in Table 1 . The description of most covariates has been previously reported in a prior study [ 49 ]. The account that follows describes only those variables unique to the present study.

The Add Health data are publicly available in both a restricted version, used in this study, and an unrestricted version with reduced cases. As a secondary analysis of existing public data, the Catholic University of America Institutional Review Board certified this study (Sponsored Research Project 200223) as exempt from data collection protocols under 45 CFR 46.101, and granted ethical approval for the data use protocol (Protocol 14-052), on 15 September, 2017. Information on how to obtain the Add Health data files used in this study is available at http://www.cpc.unc.edu/addhealth

Lifetime pregnancies and outcomes reported at all three Waves were combined to obtain a comprehensive pregnancy history. By Wave IV, 6139 ever-pregnant female respondents had reported 14,472 unique pregnancies at one or more Waves, consisting of 8900 pregnancies ending in birth, 2015 ending in induced abortion, and 2077 ending in miscarriage or other involuntary pregnancy loss. Excluding pregnancies which were ongoing at interview or for which a clear outcome was not reported left 5579 women with completed and clearly defined pregnancies at Wave IV (Wave IV Only Sample); 4523 of these reported information at all three Waves (Full Sample). Non-response on one or more of the 25 covariates and demographic control variables in the analysis reduced the sample by an additional 588 cases (13.0%), resulting in an analytic sample of 3935 cases with information on all variables at all Waves (Analysis Sample). The longitudinal analysis models employed information from all three Waves, estimating from a maximum of 11,805 wave-by-respondent cases.

Initiated by a consortium of 18 federal agencies, the National Longitudinal Study of Adolescent to Adult Health (Add Health) was designed to be the most extensive study of the health-related behaviors of U.S. adolescents during the transition to adulthood. In 1995, researchers obtained extensive measures of behavior, attitudes, and well-being from interviews with a nationally representative sample of 20,745 US adolescents (Wave I) selected from a school-based multistage cluster sampling frame stratified by school size and type, urbanicity, ethnicity and region [ 50 ]. After a one-year follow-up at Wave II, which is not used in this analysis, 12,288 members of the original sample, representing over 80% of those available, completed follow-up interviews at both Wave III in 2001–2002 and Wave IV in 2008–2009. The resulting data provide representative longitudinal health measures for this national cohort at mean ages of 15.1 years (SD 1.74, range 11–21) at Wave I (baseline), 22.0 years (SD 1.77, range 18–28) at Wave III and 28.5 years (SD 1.79, range 24–34) at Wave IV (terminus). A full description of the Add Health sample design is available at https://www.cpc.unc.edu/projects/addhealth/design/

3. Results

Several trends in the prevalence tables are worth noting. First, at all three Waves, summary mental health problems for women experiencing abortion were consistently higher than for those not experiencing abortion, including those who had not yet been pregnant. Second, at all three waves, every summary measure of mental health problem prevalence was significantly affected by the women’s experience with abortion. The number of individual outcomes affected by abortion increased over the three Waves. At Wave I, just three of the seven individual outcomes were significantly affected by abortion experience; by Wave II, five were; and by Wave IV, six of the seven were so affected. Alcohol abuse and cannabis abuse were affected at every Wave, but the effect of abortion on anxiety was not significant at any Wave. Third, the general trend for mental health problems is shaped like an upside-down “U” across the three waves, or temporally by age: problem prevalence generally increased from Wave I to Wave III (average ages 15 to 22), then declined by Wave IV (average age 28). For all women in the sample, the summary count of all seven mental health problems was 1.05 at Wave I, rose to 1.40 at Wave III, then declined to 1.01 at Wave IV. This trend is the resultant of two opposing trends by type of disorder: summary substance abuse disorders more than doubled, from 0.44 to 0.99, between Waves I and III, then dropped sharply, to 0.56, by Wave IV; by contrast, summary affective disorders declined, from 0.62 to 0.40, between Waves I and III, then rose slightly, to 0.45, by Wave IV. These opposing temporal trends were replicated in each category of pregnancy and abortion experience. Whether these observed differences are statistically significant or persist in the presence of covariate adjustments are questions to be examined below.

Table 5 reports adjusted longitudinal regression models testing the effect of intention on the question whether the abortion of a pregnancy is associated with greater subsequent mental health disorders compared to bringing the pregnancy to birth. The table shows the relationships between abortion history and subsequent mental health for ever-aborting women, measured by longitudinal regressions utilizing measures from all three waves of data and that adjust for all other pregnancy outcomes, covariates, and confounders identified in this analysis. Abortion and birth history are characterized by dichotomous measures representing whether a woman by the given age had ever experienced the abortion of a wanted pregnancy compared to only the birth of a wanted pregnancy, or only the abortion of an unwanted pregnancy compared to the birth of an unwanted pregnancy.

(2) Women ever exposed to WPA experienced an increased risk of affective mental health disorder compared to women exposed only to UPA, with RRs ranging from 1.61 to 1.77. This trend is summarized in the fact that women from age 15 to 28 (on average) who ever experienced WPA, relative to women who brought only wanted pregnancies to term, experienced overall rates of affective disorders 1.43 (95% CI 1.08–1.89) times higher ( p < 0.05) than those exposed only to UPA.

(3) Women ever exposed to WPA experienced a reduced risk of substance abuse disorder compared to women exposed only to UPA, with RRs ranging from 0.75 to 0.99. However, the confidence intervals for these RRs all included unity, and overall rates of substance abuse disorders were no different, at 0.99 RR (95% CI 0.75–1.31), for women exposed to WPA compared to those exposed only to UPA.

These findings support the hypothesis that women’s estimated risk of mental health disorder with abortion relative to birth is lower for unwanted pregnancies only than it is for all pregnancies. However, the corresponding claim that women exposed to abortion relative to birth would experience higher risk of mental health disorders with WPA compared to UPA was supported for affective disorders—for which the risk for women exposed to WPA was higher, at 1.69 (95% CI 1.31–2.18), than with only UPA, at 1.18 (95% CI 1.00–1.40)—but was not supported for substance abuse disorders—for which the risk for women exposed to WPA was not different, at 1.99 (95% CI 1.53–2.58) than with only UPA, at 2.01 (95% CI 1.69–2.38).

The risk ratios (RR) shown in Table 5 depend not only on abortion but also childbirth, expressing the ratio of the probability of mental health problems with abortion and with childbirth. To examine these effects separately, Table 6 expresses the corresponding odds ratios (OR) for each pregnancy outcome independently of the other. The ORs can be interpreted as expressing the direct or unique effect of abortion exposure, as distinct from its effect relative to birth. Appendix A Table A1 compares directly these similar but unique measures.