Around one in ten women suffer from depression, either during their pregnancy or in the first year after delivery. The consequences of this can be devastating inhibiting the woman's ability to perform daily activities, to bond with her children and to relate to her husband or partner. A study of 4,398 women in the U.S. looked at the overall rates of postnatal depression and how depression carried on from before, to during, and after, pregnancy. The researchers found that overall 15.4% of the women had suffered from depression at some point. 8.7% were depressed before becoming pregnant, 6.9% were depressed during their pregnancy and 10.4% were depressed after their baby had been born. Of the women who had been depressed before becoming pregnant 56.4% were also diagnosed with depression during their pregnancy and of those who were depressed after their pregnancy 54.2% had had diagnoses of depression either while they were carrying their baby or in the 39 weeks beforehand. Most of the women had received antidepressants although they were less likely to take them while they were pregnant. The researchers concluded that there was a high degree of continuity between women's mental states before, during and after pregnancy and that this meant that there should be a similar continuity of care in the treatment of the women.
Dietz, Patricia M. ... [et al] - Clinically identified maternal depression before, during, and after pregnancies ending in live births American Journal of Psychiatry October 2007, 164(10), 1515-1520