Munk-Olsen et al

Induced First-Trimester Abortion and Risk of Mental Disorder. Trine Munk-Olsen, Ph.D., Thomas Munk Laursen, Ph.D., Carsten B. Pedersen, Dr.Med.Sc., Øjvind Lidegaard, Dr.Med.Sc., and Preben Bo Mortensen, Dr.Med.Sc. N Engl J Med 2011;364:332-9.

Abstract

Background
Concern has been expressed about potential harm to women’s mental health in association with having an induced abortion, but it remains unclear whether induced abortion is associated with an increased risk of subsequent psychiatric problems.

Methods
We conducted a population-based cohort study that involved linking information from the Danish Civil Registration system to the Danish Psychiatric Central Register and the Danish National Register of Patients. The information consisted of data for girls and women with no record of mental disorders during the 1995–2007 period who had a first-trimester induced abortion or a first childbirth during that period. We estimated the rates of first-time psychiatric contact (an inpatient admission or outpatient visit) for any type of mental disorder within the 12 months after the abortion or childbirth as compared with the 9-month period preceding the event.

Results
The incidence rates of first psychiatric contact per 1000 person-years among girls and women who had a first abortion were 14.6 (95% confidence interval [CI], 13.7 to 15.6) before abortion and 15.2 (95% CI, 14.4 to 16.1) after abortion. The corresponding rates among girls and women who had a first childbirth were 3.9 (95% CI, 3.7 to 4.2) before delivery and 6.7 (95% CI, 6.4 to 7.0) post partum. The relative risk of a psychiatric contact did not differ significantly after abortion as compared with before abortion (P = 0.19) but did increase after childbirth as compared with before childbirth (P<0.001).

Conclusions
The finding that the incidence rate of psychiatric contact was similar before and after a first-trimester abortion does not support the hypothesis that there is an increased risk of mental disorders after a first-trimester induced abortion. (Funded by the Susan Thompson Buffett Foundation and the Danish Medical Research Council.)

Limitations

1. The pre-event (abortion or childbirth) measure of mental health was limited to only 9 months.  This period was chosen to include (on average) only the time that a delivering woman was pregnant.  It therefore totally ignores the pre-pregnancy mental health of delivering women. By contrast, for women who had abortions this nine month pre-event window includes six to eight pre-pregnant months plus one to three months during which the woman discovered she was faced with an unintended pregnancy and was deciding on an abortion.  While it is important to control for prior mental health, it would have been far preferable to use the the full life history of psychiatric treatments for women in both groups, or at least a five year history prior to the pregnancy. Such data was available to the researchers.  Why it was not used is unclear.  At the very least, the control period should have been based on a period of time estimated to have been before the women in both groups became pregnant. Furthermore, while the researchers did exclude women who had any prior history of inpatient psychiatric care, they did not control for prior history of outpatient psychiatric care.  In other words, we do not know if there were any differences in the rates of outpatient treatment between the two groups.  Bottom line: the control for prior mental health history in this study is very weak and may even lead to misleading results. To spell out this limitation more fully, this nine-month window on "prior" mental health is problematic for the following reasons.

• Women who are planning and excited about having a baby may be less likely to seek mental health.  This is why the incidence rate is so low 3.9%.  With only a nine-month pre-event window, the authors are even excluding those women who may have been experiencing anxiety or other problems as they struggled to become pregnant.  So this measure of mental health during a first pregnancy is a poor indicator of mental health prior to a first delivery.
• Given the lack of more complete controls for mental health history suggested above, we must assume that since both groups had no prior history of outpatient mental health care prior to their first pregnancies, the mental health of both groups was very similar prior to becoming pregnant.  The three fold increase in mental health treatments prior to abortion (14.6%) compared to women who gave birth (3.9%) would therefore appear to be most likely explained by stress these women faced discovering they were faced with an unplanned pregnancy and, in many cases, the concurrent disruption of relationships with male partners, parents, employers and others. It is not surprising, then, that many of these women facing the stress of abortion decision-making sought psychiatric advise at a much more elevated rate than they had in the past.
• It is a common failure in abortion research to fail to identify the difference between pre-pregnancy mental health and pre-abortion mental health.  Proponents of the view that abortion contributes to mental health problems do not question that the mental health stressors include experiences and factors which occur between the impregnation and abortion.  Indeed, it is proposed that abortion is both a stress releiver (resolving some of these stresses) and a stress inducer (creating new stresses).
• high rate of pre-abortion mental health problems is construed to indicate that women who choose abortion will often experience mental health problems based on factors other than the procedure. In fact, the women in the sample are quite unlikely to fall into this “vulnerable” category since none of the women included in the study had any history of psychological diagnoses prior to 9 months before the abortion. These researchers used a window of 0-9 months to measure pre-abortion mental health; however, the assessment should instead have been before the pregnancies were detected. The data do indicate that rates of mental health problems are significantly higher after abortion compared to after childbirth (15.2% vs. 6.7%) and compared to not having been pregnant (8.2%). The bottom line is the fact that they found comparable rates before and after abortion does not negate a possible causal link between abortion and mental health. This is true because many women were likely disturbed to the point of seeking help, because they were pregnant and contemplating an abortion or had already chosen one and were awaiting the procedure. There are numerous published studies indicating high levels of stress among women facing an unplanned pregnancy and considering an abortion.

Other Studies

Curiously they did not follow the research approach used in previous Danish Study Hospitalization for Mental Illness among Parents after the Death of a Child