Women are not at increased risk of being treated for a mental disorder following a first-time, first-trimester abortion, according to a study that used data from Danish national registries.1 However, women’s risk of mental disorder is elevated following their first live birth. The incidence rates of first-time psychiatric contact among females who had an abortion in 1995–2007 were statistically indistinguishable before and after the abortion (14.6 and 15.2 per 1,000 person-years, respectively), whereas the rate jumped significantly between the time preceding and the period following childbirth (from 3.9 to 6.7 per 1,000 person-years). The increase in the risk postpartum was most dramatic in the early months following delivery.

To determine whether women who have induced abortions are at risk of having subsequent mental health problems, investigators linked data from three national population and medical registries on Danish-born females who had a first-time, first-trimester induced abortion or a first live birth between 1995 and 2007. They excluded those who had had inpatient psychiatric care more than nine months before the abortion or birth. Survival-analysis techniques were used to follow each female from nine months before the abortion or birth to 12 months after. Incidence rates of psychiatric care were calculated for the periods before and after the birth or abortion.

Among the 84,620 females who had a first-time, first-trimester abortion during the study period, 1.0% received inpatient or outpatient psychiatric care in the nine months preceding the abortion, and 1.5% did so in the subsequent 12 months. The corresponding incidence rates of contact were 14.6 and 15.2 per 1,000 person-years, respectively; these rates were not significantly different. Among the 280,930 females who had their first live birth during this period, 0.3% and 0.7% had first-time psychiatric contact in the previous nine months and the following year, respectively; the corresponding incidence rates were 3.9 and 6.7 per 1,000 person-years. Notably, the difference between these rates was statistically significant.

In the first month following an abortion or birth, the two groups of females had similar risks of psychiatric contact; in each subsequent month, the risk was significantly higher for those who had had an abortion than for those who had given birth. In analysis that adjusted for age distribution and calendar period differences between the abortion and birth cohorts, the risk of psychiatric contact remained steady throughout the period following an abortion. However, the risk among females who gave birth was sharply higher in the first month of the postpartum period than in the nine months preceding birth, and it remained elevated for sixth months after delivery.

Psychiatric contact for specific types of disorders was more likely following an abortion than before, but these differences appeared in only a few of the postabortion months, and no consistent increases in risk were found. In contrast, among those who had a birth, the risk of psychiatric contact for the same disorders was consistently elevated 1–9 months postpartum (relative risk ratios, 1.3–4.5). Finally, in contrast with earlier reports, this study found no associations between mental health problems following abortion and younger age or parental history of mental disorder.

The researchers believe that their use of comprehensive national registers was a major strength of the study. Yet they also identified several limitations: the lack of information on whether terminated pregnancies were unwanted and on females who had mental health problems but did not seek care, and the exclusion of females with a history of psychiatric contact. Given the relatively high rates of psychiatric contact in the abortion group both before and after the abortion, the investigators assert that females who have a first-time, first-trimester abortion appear to constitute a population with elevated psychiatric morbidity. However, they state that their findings “[do] not support the hypothesis that there is an overall increased risk of mental disorders” following first-trimester abortions.—J. Thomas