Depression During Pregnancy Is a Risk Factor for Postpartum Depression, Does Timing Matter?

About 10% to 15% of women experience depression during the first year of childbirth. Some of the earliest studies identified depression during pregnancy as a robust predictor of postpartum depression. Other studies have indicated that for many women with postpartum depression, depressive symptoms actually begin to emerge during pregnancy and worsen after childbirth.

A more nuanced understanding of the continuum of depressive symptoms across pregnancy and the postpartum period has important clinical implications and could inform the timing of screening for perinatal mood and anxiety disorders.

A recent study conducted a systematic review and meta-analysis estimates the prevalence of postpartum depression (PPD) at different timepoints in women who experienced antenatal depression at different times during pregnancy.

The researchers identified cohort studies examining the prevalence of PPD in women who had depression during pregnancy (antenatal depression or AD) and studies examining the association between AD and PPD. The analysis included 88 cohort studies with a total of 1,042,448 perinatal women. 

• About 37% of the pregnant women who had AD later experienced PPD. Women with antenatal depression had a 4.58-fold greater risk of developing PPD (OR: 4.58; 95% CI = 3.52-5.96). 
• The likelihood of having PPD were higher when antenatal depression was observed during the first or the third trimester compared to the second trimester. About 12.8% of PPD cases were attributable to AD.
• Among women with PPD, 16.3% also had depression during pregnancy.

In this meta-analysis including over one million perinatal women, women who experienced depression during pregnancy were about four times as likely to experience PPD compared to women with no depression during pregnancy, a finding that is similar to previous studies. In addition, depressive symptoms noted during the first trimester were as strongly associated with PPD as depressive symptoms during the third trimester. 

What Are the Clinical Implications?

This study indicates that women who experienced depression during pregnancy had a more than fourfold greater risk of developing PPD than women without antenatal depression. The odds of having PPD were higher when antenatal depression was observed in the first or third trimester compared to the second trimester. The findings of the current study are consistent with previous studies indicating that depression during pregnancy is one of the most robust predictors of PPD.

While this study and many others have identified depression during pregnancy as a risk factor for PPD, we don’t know exactly how it confers risk. Some have hypothesized that a dysfunction in the neuroendocrine system and vulnerability to shifts in the hormonal milieu may explain the association between antenatal depression and PPD. Another hypothesis is that depressive episodes during pregnancy may be associated with inflammation that increases vulnerability to stressors after childbirth and subsequent depressive episodes. Another explanation is the “scar hypothesis”; it is thought that a depressive episode leads to lasting changes in personality, behavior and self-concept that render a person more vulnerable to depression in the future.

Questions remain; however, this study underscores the importance of screening for depression during pregnancy. Screening using standardized questionnaires represents an easy, low-cost means of identifying women at risk for PPD. Furthermore, the study indicates that screening during the first trimester is as important as screening during subsequent trimesters. Moreover, if we identify women with depressive symptoms during the first trimester, we have time to institute nonpharmacologic and pharmacologic interventions to treat the current episode of depression and to reduce risk for PPD.

Ruta Nonacs, MD PhD

References

Dlamini LP, Amelia VL, Shongwe MC, Chang PC, Chung MH. Antenatal depression across trimesters as a risk for postpartum depression and estimation of the fraction of postpartum depression attributable to antenatal depression: A systematic review and meta-analysis of cohort studies. Gen Hosp Psychiatry. 2023 Nov-Dec; 85:35-42.