Although most people tend to think of pregnancy as a time of emotional well-being, depression is relatively common, affecting about 1 in 10 women. While there are obvious concerns related to the use of antidepressants during pregnancy and the effects of these medications on the developing fetus, less attention has focused on the impact of depression itself on the pregnancy. A recent study suggests that women with depression may be at greater risk for preterm labor.

In this cohort study conducted in France, 634 pregnant women were surveyed and levels of anxiety and depression were assessed using Spielberger’s State-Trait Anxiety Inventory and the Edinburgh Depression Scale (EPDS). Spontaneous preterm labor was observed in 11.4% of the women. Those with depression (as defined by an EPDS score of 15 or greater) were twice as likely to have preterm labor than non-depressed women. The association between depression and preterm labor was even stronger in women who were underweight prior to pregnancy (a known risk factor for preterm labor). Higher levels of anxiety (above the 75th percentile) were also associated with a slight increase in risk, but this finding was statistically significant only among women with a history of preterm labor.

These findings suggest that depression and anxiety, particularly when combined with other medical risk factors, are associated with higher rates of preterm labor. The mechanism by which depression and anxiety may exert this effect is unclear; however, one hypothesis is that women who experience depression or anxiety 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.

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.