Depression is not uncommon in pregnant women, especially in the second and third trimesters of pregnancy, according to researchers who reviewed 21 studies, involving a total of more than 19,000 women, in the April issue of Obstetrics and Gynecology. Their analysis shows that the prevalence of depression is 7.4 per cent in the first trimester of pregnancy, 12.8 per cent in the second and 12 per cent in the third.