An abbreviated version of this post appeared on the Center for Health Journalism Blog on February 22, 2019.
The most common postpartum depression (PPD) statistic is 11 percent: according to the Centers for Disease Control and Prevention (CDC), 11 percent of women experience symptoms of depression after their baby is born.
Ovia Health data from more than 500,000 women suggest this disease is much more prevalent: 19 percent scored 13 or higher on the Edinburgh Postnatal Depression Screen, the standard clinical screen.
I think the higher prevalence rates are more accurate. This blog will be a wonky explanation of why that is. But for those of you who have a short attention span and want the punchline, here it is: society stigmatizes PPD and the way we screen for this disease makes it less likely that women and their clinicians will identify genuine suffering.
Data from studies conducted in the typical way put the prevalence in the United States at 9-16 percent. The CDC study tends to be cited most frequently. The CDC surveys women after delivery in an ongoing initiative, the PRAMS survey, to understand attitudes and experiences related to pregnancy and childbirth. There are three major problems with the CDC study: depressive symptoms are assessed with only two questions, the survey was answered on average four months after delivery – a timeframe that doesn’t correlate with a typical clinical ‘check-in’ for most women – and the authors of the CDC study acknowledge that the two questions only ‘detect’ depression when it is present 58% of the time and so their study may underestimate the prevalence of the condition. Other studies base their findings on face-to-face interviews, use of the Edinburgh screen, medical records, and structured clinical interviews.
The problem with many of these study methods is that they are all subject to face validity. Neuropsychologist Dr. Kelly Lowery (who, coincidentally, is married to this blog’s author) was kind enough to explain face validity and why it matters here: “These surveys tend to ask questions in such a way that the individual can guess what construct is being measured. That is, the fact that the scale is measuring depression becomes transparent to women. This is tricky because women often feel societal pressure to describe the birth of a child and motherhood as ‘all good’ and, thus, they may under-report their symptoms and challenges with adjustment.”
Ovia uses the Edinburgh screen, which is also subject to face validity. Furthermore, it’s very possible that women who are experiencing depressive symptoms are more likely to take the Edinburgh depression survey in Ovia than women who are not depressed, artificially inflating the prevalence of the condition among Ovia users.
“I am convinced that the prevalence of PPD and other mental health issues during pregnancy and postpartum is significantly higher than national estimates,” said Melanie Thomas, M.D., who specializes in women’s mental health at Zuckerberg San Francisco County Hospital. “For many women, including those who have experienced structural racism and violence, there is no evidence that they will receive the support they need should they report depressive symptoms.”
The reason I think Ovia data are more accurate is that women develop a confidential and trusting relationship with the Ovia apps. They know no one will see their results, no one will shame them, and the experience is, in some respects anonymous, at least in comparison to their relationship with their healthcare provider. Ovia won’t judge them. They are more likely to tell the truth.
This gets to the critical issue of stigma as it relates to mental health, and particularly to PPD. It is well established that patients suffering from mental health disorders are less likely to seek treatment due to the stigma associated with their diagnosis. Although there is vanishingly little research on the influence of social stigma on reporting of PPD, it’s reasonable to assume that stigma exerts the same impact on PPD as it does on other mental health conditions. Ask almost any mother and she will tell you that, except for exhaustion, negative emotions about being a new mom generate antipathy – sometimes even from those who are supposed to be her sources of support. Nancy Byatt, M.D., a psychiatrist specializing in women’s mental health at the University of Massachusetts Medical School notes that, “Having a baby can be extraordinarily challenging and every women deserves support. While it may be hard to share concerns about depression or anxiety, their providers and loved ones want to know if they are suffering so they can help them get the help they need and deserve.” The American College of Obstetricians and Gynecologists (ACOG) recommends that obstetric care providers screen women for depression in pregnancy and after delivery, points out Tiffany Moore-Simas, M.D., an OBGYN specializing in women’s mental health. “Moreover, they should engage a woman in care, and provide or refer to treatment as appropriate,” she said. She is hopeful that by screening women and thus initiating conversations about mental health, that stigma can be diminished and ideally eliminated.
If Ovia’s data on more than 500,000 women is correct, the implications for maternal mental health are far-reaching. First, the disease may impact twice as many women as public health advocates assume. Second, traditional methods of screening are failing women, because they encourage women to under-report suffering. Third, as a society we are stigmatizing a medical condition that is insidious and very very common.
 Technically, there is an important difference between women who endorse symptoms of depression on any of the questionnaires that screen for depressive symptoms, and the diagnosis of depression based on a clinical assessment. Although it is probably more accurate to discuss the prevalence of symptoms here, instead of the prevalence of a disease, I’m going to conflate the two given the strong association between high screening scores and the diagnosis of the disease.
 Postpartum depression is much more common among young women, poor women, women from ethnic and racial minority groups, and varies significantly from one state to another.
 1) “Since your new baby was born, how often have you felt down, depressed, or hopeless?” and 2) “Since your new baby was born, how often have you had little interest or little pleasure in doing things?”