What's New in Perinatal Depression?

In 2009, several studies shed light on the genetics, differential diagnosis, and treatment of postpartum depression. Other findings added to the ongoing clinical challenge of determining whether to prescribe antidepressants during pregnancy.

Genetic underpinnings of postpartum depression were explored in a two-part study involving 1126 women with family histories of bipolar disorder or early-onset major depression (Am J Psychiatry 166:1229). In the genome-wide linkage study, self-reported postpartum mood symptoms were linked with two chromosomal regions; the follow-up association study suggested possible associations with HMCN1, which contains four estrogen-receptor binding sites and expression of which is altered by the postpartum drop in estrogen levels, and METTL13, implicated in estrogen-receptor–induced gene transcription. However, these findings require replication because of diagnostic heterogeneity, lack of rigorous diagnostic assessments, multiple tests in the association study, and linkage results that differed from those in a previous study of postpartum psychosis. Still, this study remains important because of its focus on the familial aggregation of, and potential genetic contribution to, postpartum mood disorders.

Postpartum disorders include bipolar II disorder, and the rate of postpartum episodes (mostly, depression) in women with bipolar spectrum disorders is high (Am J Psychiatry 166:1217). Misdiagnosing major depression in these bipolar patients can lead to inappropriate antidepressant monotherapy, treatment nonresponse, and an unstable clinical course.

Also in 2009, promising studies of psychological interventions for mild postpartum depressive symptoms demonstrated efficacy of peer telephone support for prevention and cognitive-behavioral or person-centered psychological interventions for treatment. Similarly, interpersonally focused psychotherapy was shown to be superior to enhanced usual care in perinatal depression.

The need for antidepressant treatment remains great. Untreated depression during pregnancy is associated with poor prenatal care, poor pregnancy outcomes, and postpartum depression. Women with histories of recurrent major depression who discontinue antidepressants in pregnancy have high relapse rates.

Still, researchers continue to detail potential risks of antidepressant use during pregnancy. In 5731 women without hypertension histories, the self-reported rate of preeclampsia was 15.2% in those continuing SSRI treatment after the first trimester, 5.9% in women taking non-SSRI antidepressants, 3.7% in those discontinuing SSRIs, and 2.4% in those not receiving SSRIs. A Danish registry study, which controlled for smoking and maternal age but not for presence or severity of depression, associated SSRI exposure during pregnancy with an increase in the rate of cardiac septal defects from 0.5% to 0.9%. In a Danish registry study, the risk for preterm delivery in SSRI-treated women was twice that of women with no SSRI treatment, regardless of whether they had psychiatric histories. In a study with smaller sample sizes but better-characterized psychiatric diagnoses, both SSRI treatment and untreated depression throughout pregnancy were associated with higher rates of preterm birth than no depression, depression but no SSRI treatment, or depression or treatment during only part of pregnancy.

Thus, the informed-consent process for SSRI treatment during pregnancy should include newly identified risks (cardiac septal defects, gestational hypertension, and preeclampsia), and previously identified ones (miscarriage, low birth weight, preterm birth, transient neonatal symptoms, and persistent pulmonary hypertension of the newborn). However, many of these studies are confounded by effects of smoking, alcohol and drug use, poor prenatal care, and depression itself. Discontinuing SSRIs poses significant risks to mothers with severe recurrent depression and their children. Furthermore, switching to a non-SSRI antidepressant entails risk for nonresponse, and very little is known about risks in pregnancy of newer antidepressants (e.g., bupropion, serotonin-norepinephrine reuptake inhibitors).

Clinicians may wish to use the algorithms for depression treatment during pregnancy that were developed by the American Psychiatric Association and American College of Obstetricians and Gynecologists. The algorithms emphasize the importance of adequate treatment, risk for relapse in women with severe recurrent major depression who discontinue medication, psychotherapy for mild-to-moderate depression, the need for collaborative treatment decisions by clinician and patient, possible use of ECT for severe depression, and psychiatric referral for severe depression, acute suicidality, bipolar disorder, or psychosis.

Increased clinical and research attention to perinatal mood disorders promises to help clinicians better understand, diagnose, and treat these conditions. For now, however, treatment decisions during pregnancy continue to require collaboration between clinician and patient, weighing potential risks of medication against those of untreated depression.