Depression during pregnancy. A meta-analysis was conducted in 2004 into the prevalence of prenatal depression (Xxxxxxx, Xxxxxxxx, Xxxxxx, Xxxxx, & Xxxxxxxx, 2004). The meta-analysis included studies published since 1980. Twenty-one studies were identified, seven of which were based on clinical diagnoses of depression rated through structured clinical interviews (Schedule for Affective Disorders and Schizophrenia; SADS), whilst the remaining studies were based on ratings of depression captured through self-report measures such as the Edinburgh Postnatal Depression Scale (EPDS) and the Xxxx Depression Inventory (BDI). The authors report the point prevalence of depression by trimester, with rates of 7.4%, 12.8% and 12.0% in the first, second and third trimesters, respectively. Prevalence estimated through structured interviews did not differ significantly from rates attained through the EPDS, but were significantly lower that rates attained through the BDI. In a further meta-analysis, Xxxxx and colleagues (2005), reviewed studies where depression during pregnancy had been rated through only structured clinical interviews. The authors report a period prevalence rate (conception to birth) for MDD of 12.7%, with this rising to 18.4% when ratings of minor depression (akin to the DSM-IV diagnosis of major depressive disorder not otherwise specified [MDD NOS] ; American Psychiatric Association, 2000) were included. In both studies there were noteworthy methodological flaws, such as the exclusion of women with previous psychiatric histories and of low socioeconomic status. Given that both of these factors are well-known risk factors for depression (Xxxxxx & Xxxxxx, 2009), it is likely that these estimates are conservative, and thus these findings need to be interpreted bearing these caveats in mind.
