Depression: Is Pregnancy Protective?

In this issue, the article by Ko et al. ¹ has a number of important findings. The authors used a large dataset (National Surveys on Drug Use and Health) of 77,415 women between the ages of 18 and 44 in order to determine the past-year prevalence of depression, diagnosis and treatment of depression, and barriers to seeking care in both pregnant and nonpregnant women. Using the DSM-IV definition of a major depressive episode (MDE), the authors determined that 10.9% of the women reported symptoms consistent with an MDE in the past year. Strikingly, 58.8% of those who met criteria for an MDE never received a diagnosis of depression, and pregnant women had a higher prevalence of undiagnosed depression (65.9%) compared to nonpregnant women (58.6%), although this was not statistically significant. Women with undiagnosed depression were more likely to be from a racial or ethnic minority. The most common barriers to care were cost, stigma, and opposition to treatment, which likely also reflect the stigma associated with psychiatric illness.

This study underscores the continuing struggle to adequately diagnose and treat major depression and other psychiatric disorders. It also points out significant racial disparities in receiving care for psychiatric illness and supports the idea that the stigma of psychiatric illness continues to be one of the main reasons that people oppose and do not seek treatment for depression. The study by Ko et al. ¹ nicely outlines the biggest challenges that psychiatry faces as a field: disparities in access to diagnosis and treatment and the stigma associated with psychiatric illness. One must wonder if 10% of women in the United States developed a particular cancer with at least a 10% mortality rate and nearly 60% went undiagnosed, with higher rates of undiagnosed cancer in minority groups, would there not be public outrage? Unlike the situation in most other fields of medicine, a majority of psychiatric patients are disenfranchised in some way, and I would argue that it will take a large shift in the public's perception of psychiatric illness to achieve improved rates of diagnosis and treatment.

Another interesting finding in the Ko et al. article is that significantly less pregnant women (7.7%) reported a past-year MDE compared to nonpregnant women (11.1%, p<0.001). For many years, pregnancy has been considered to be protective against the development of depression, primarily because of the lower suicide rate during pregnancy and during the 2 years after giving birth. ^2,3 Is pregnancy, therefore, a protective factor against the development of depression? Many would argue no. Vesga-Lopez et al. ⁴ examined the rates of DSM-IV-defined major depression diagnosed by a face-to-face standardized interview in pregnant and nonpregnant women from the general population. There was no difference in risk between the two groups. In contrast, the postpartum time period clearly was a period of increased risk for the development of an MDE. This would argue against pregnancy being protective and instead shows an equivalent risk both during and outside of pregnancy.

The role of pregnancy in the development of major depression also depends on the population being studied. In women with a history of major depression who stop their antidepressant medications for pregnancy, close to 70% will relapse with an MDE during pregnancy. ^5,6 Clearly, pregnancy is not protective in this population of high-risk women.

Finally, though Ko et al. demonstrate a statistically significantly lower prevalence rate during pregnancy, their finding that pregnant women had a (nonsignificantly) higher rate of undiagnosed depression indicates that pregnancy is certainly not protective against receiving a diagnosis of depression. One might have expected a lower rate of undiagnosed depression in pregnant women given that they (1) interact with doctors frequently during pregnancy and (2) are more likely to have insurance. This higher rate could reflect a number of different issues. The authors ¹ point out that psychiatric disorders are often undiagnosed by obstetricians ⁷ and gynecologists ^{7 –9} and that screening rates are low in these settings likely because of a lack of referral sources for patients once they are identified as having depression. ¹⁰ Another contribution to the lower rate of diagnosis may be that many symptoms of depression overlap with side effects of pregnancy: changes in sleep, appetite, energy, and concentration can be thought to be secondary to pregnancy and not interpreted as part of a mood disorder.

The idea that pregnancy is protective against depression is an attractive one. It fits with our romantic notions of motherhood. Although the data of Ko et al. ¹ support this notion, more importantly, their article dramatically demonstrates that even if there are lower rates of depression during pregnancy in some populations, it remains undiagnosed particularly in racial and ethnic minorities. Depression remains undiagnosed despite the fact that pregnant women are seen more often in the medical system and are more likely to have insurance that would allow treatment. From this perspective pregnancy is certainly not protective.

The stigma associated with psychiatric illness remains one of the main barriers to seeking psychiatric care. If regular screening for depression were instituted in primary care sites and psychiatric services were more readily available to support such screening, the stigma surrounding a diagnosis of major depression would likely decrease as both patients and doctors became used to the idea that it is as important to diagnose major depression as it is for other medical illnesses. Psychiatry and the medical establishment as a whole need to work together to decrease stigma and other barriers to proper diagnosis and treatment for psychiatric illness so that not only pregnancy but the system as a whole can become protective against depression.