A new study published in the February issue of Archives of General Psychiatry suggests that a simple blood test can predict whether a woman is likely to develop postpartum depression (PPD).

Researchers from the University of California, Irvine, analyzed blood samples from 100 pregnant women during weeks 15, 19, 25, 31, and 37 of their pregnancies, and tested the levels of a hormone, placental corticotropin-releasing hormone (pCRH), found in the placenta. The women were also screened for depression during the last four visits, and then again postpartum. Sixteen of the 100 women in the study developed postpartum depression symptoms. In those sixteen women, the level of pCRH found at week 25 of the pregnancy was high.

Postpartum depression affects between 10 and 13% of pregnant women and new mothers. It's still not clear what causes the condition, but a history of depression or PMS, stress and anxiety during pregnancy, fluctuating hormones and a lack of social support are all believed to be risk factors.

The findings suggest that the blood test could one day become part of standard prenatal care, just as screening for gestational diabetes is right now. And in the same way that a woman with gestational diabetes receives special care to prevent adverse effects for the developing fetus, a woman whose blood test has indicated that she is susceptible to postpartum depression could take steps to prevent it, and receive quick treatment if PPD develops.