Depression
Women in their reproductive years constitute the population at greatest risk for major depression. However, an increase in somatic symptoms has been noted on self-reported depression scales by pregnant women who do not meet the criteria for major depression.¹² Depressive symptoms such as fatigue and changes in sleep and appetite that occur in pregnant women can be difficult to distinguish from the normative experiences of pregnancy.  Factors that appear to confer heightened risk for depression during pregnancy include (1) a prior history of depression,¹³ (2)  young age,¹⁴  (3)  limited social support,¹⁵  (4)  living alone or having a greater number of children,¹⁶ (5) marital conflict,¹⁷ and (6) ambivalence about the pregnancy.¹⁷

Literature on the prevalence of depression during pregnancy is frequently complicated by the use of various methodologies, procedures, and study populations. Controlled studies that systematically evaluate the course of depression during pregnancy may arrive at different conclusions. In a controlled prospective study,¹² 182 gravid and 179 nongravid women were evaluated prospectively using Research Diagnostic Criteria for major and minor depression,  and the rates of depression were equal in gravid and nongravid women. Investigators reported that the highest level of depressive symptomatology occurred at 34 to 38 weeks gestation. Another study that assessed mood state during pregnancy¹⁷ noted that many patients who were depressed in the first trimester frequently experienced improvement in the second and third trimesters.

While these 2 studies seem to be at odds, the psychotropic drug status was not mentioned in either study; thus, it is unclear whether the subjects’  mood status might have changed as a function of antidepressant treatment or medication discontinuation.

Alterations in antidepressant blood levels may also account for mood changes in pregnant women; observed antidepressant levels reportedly decrease during pregnancy.^18–20  Consequently,  women who continue antidepressant treatment throughout pregnancy may have emerging depressive symptoms secondary to a fall in blood antidepressant levels as the pregnancy progresses.

The decrease in blood antidepressant levels may be the result of a pregnancy-associated increase in plasma volume occurring by the third trimester or by an increase in hepatic microsomal enzyme-metabolizing activity and renal clearance rates.¹⁸  Blood levels of antidepressants, particularly the tricyclic antidepressants,  can be monitored in pregnant women and dose adjustments made as necessary.

The risk for relapse of depressive symptoms is well described for nongravid depressed patients with recurrent mood disorders who discontinue antidepressant medication.^6,14,21,22 Recurrence rates are estimated to be as high as 50% within 6 months following discontinuation of antidepressant treatment. However, little is known about the risk for relapse of depressive symptoms in pregnant women with a prior history of depression who discontinue their antidepressant medication. Depressive relapse during pregnancy is of particular concern because of an increased risk of inadequate prenatal care, poor maternal/fetal nutrition, obstetric complications, and postpartum depression.

^13,23–25 Additionally,  the potential impact that hypothalamic-pituitary-adrenal dysregulation associated with depression has on fetal well-being is of at least theoretical concern.

Decisions regarding medication discontinuation during pregnancy should be made carefully and should take into account the previous psychiatric history and its severity as well as chronicity of the illness as measured by the number of previous episodes of depression.