A new study reported in Human Reproduction supports what many other studies have found, that untreated depression during pregnancy increases the likelihood of delivering before 37 weeks gestation.
In this prospective cohort study from by De-Kun Li and colleagues at the Kaiser Foundation Research Institute, women were screened for depression during the first trimester, at approximately 10 weeks gestation, using the Center for Epidemiological Studies Depression Scale (CES-D). 791 women completed the screening and delivered a live baby. Women who went on to miscarry before 20 weeks gestation were excluded from the study.
41.2% of women reported having significant depressive symptoms (CES-D > 16) and 21.7% of those women had severe depressive symptoms (CES-D > 22). After adjusting for potential confounding variables (e.g., maternal age, education, race/ethnicity, gravidity, history of miscarriage, preterm delivery or low birthweight, vitamin use, vomiting and smoking during pregnancy), it was demonstrated that women with significant depressive symptoms were almost twice as likely to deliver a preterm baby (before 37 weeks gestation) than those women without depressive symptoms. The risk increased with the greater severity of depression.
Several other factors were found to exacerbate the effect of depressive symptoms on the risk of preterm delivery; these included low education level, a history of fertility problems, obesity, and life stressful events. Few women in this study were prescribed antidepressants (only 1.5%), indicating that it was the depression itself – rather than the medication used to treat the depression – that increased risk for preterm delivery.
Over the last decade, several other studies have found an association between depressive symptoms during pregnancy and risk for preterm delivery (reviewed in Bonari, 2004). Researchers hypothesize that increased levels of stress hormones associated with depression and anxiety may decrease blood flow to the placenta and may also help to trigger preterm labor and delivery.
What this study also indicates is that a significant proportion of women experience depressive symptoms during pregnancy and that most women with moderate to severe depression go untreated. Although many women and clinicians are reluctant to use antidepressant medications during pregnancy, this study indicates that depression during pregnancy carries its own set of risks to the fetus. Thus, women who suffer from depression with depression are encouraged to seek treatment. While psychotherapy is an effective treatment for depression, many women, especially those with more severe depressive symptoms may benefit from treatment with an antidepressant during pregnancy.
Kim Pearson, M.D.
Li, D. Liu L., Odouli R. Presence of depressive symptoms during early pregnancy and the risk of preterm delivery: a prospective cohort study. Human Reproduction 2008 Oct 23 (E-published ahead of print).