Some, but not all, studies have indicated that depression during pregnancy increases the risk of preterm birth. A recent study published in the American Journal of Obstetrics and Gynecology is one of the largest to address this question.
In this study, 14,175 pregnant women were screened using the Edinburgh Postnatal Depression Scale (EPDS) between 24 and 28 weeks of gestation. A score ?12 (or thoughts of self-harm) was used to identify women at risk for depression.
1298 (or 9.1%) of the women screened positive on the EPDS. When compared to women with lower EPDS scores, these at-risk women were more likely to have a preterm birth at of <37, <34, <32, and <28 weeks of gestation.
Adjusting for potential confounding factors including maternal age, race/ethnicity, prior preterm delivery, and insurance status, the researchers observed a persistent association between antenatal depressive symptoms and preterm birth (adjusted odds ratio, 1.3). This association was also observed after multiple gestations were excluded from the analysis (odds ratio, 1.7).
Other smaller studies have yielded similar findings:
Fransson et al: 2904 pregnant women screened with EPDS, odds ratio for pteterm birth 1.56 in women scoring >12 on the EPDS.
Dayan et al: 634 pregnant women screened with EPDS, odds ratio of preterm birth 2.1 in women with >15 on EPDS, risk was greatest in women with other risk factors (e.g., low body weight, history of preterm birth).
These findings suggest that depression, particularly when combined with other medical risk factors, are associated with higher rates of preterm labor. The mechanism by which depression may exert this effect is unclear; however, one hypothesis is that women who experience depression exhibit hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis and consequently have elevated levels of circulating cortisol and corticotropin releasing factor (CRF), which is an important component of a system that controls the normal maturation of the fetus and signals the initiation of labor.
Ruta Nonacs,MD PhD
Dayan J, Creveuil C, Herlicoviez M, Herbel C, Baranger E, Savoye C, Thouin A. Role of anxiety and depression in the onset of spontaneous preterm labor. American Journal of Epidemiology. 155: 293-301, 2002.
Fransson E, Örtenstrand A, Hjelmstedt A. Antenatal Depressive Symptoms and Preterm Birth: A Prospective Study of a Swedish National Sample. Birth 2010; 38: 1523-536.
Straub H, Adams M, Kim JJ, et al. Antenatal depressive symptoms increase the likelihood of preterm birth. Am J Obstet Gynecol 2012;207.