Depression following pregnancy, commonly known as postpartum depression (PPD), is a mood disorder, a type of clinical depression, causing crying episodes, anxiety, sadness, low energy, changes in sleeping/eating patterns, reduced desire for sex, and irritability. The common stat is that it affects 11 to 20 percent of new moms, but other researchers have a more nuanced view and believe PPD has a more wide-ranging effect. In either parse, by estimates of the Centers for Disease Control and Prevention, only 15 percent of the women suffering from PPD seek the proper mental health assistance.

If doctors could somehow predict what women would fall prey to PPD in advance of the birth, it would inevitably lead to better care. A team of scientists at UCLA has been studying PPD, and may have just found the predictors to make this happen.

Between 12 and 36 weeks gestation, 343 pregnant women who were not suffering from depression at the time of conception but who had been diagnosed with major depressive disorder at some time prior to pregnancy were enrolled into the study. Women with schizophrenia, bipolar disorder or a substance abuse disorder were not included. This last is meaningful because women with a history of depression are particularly vulnerable to depression after they give birth.

A psychiatrist evaluated each woman's mood and psychotropic medication at least twice, once within 60 days before their babies' due dates and again within 60 days after delivery. Structured, clinical interviews were used. These included questions about work activities and difficulties, insomnia and suicidal thoughts.

Researchers were surprised to learn that among women with prior histories of major depressive disorder but who were not depressed when they become pregnant, only 11 percent developed postpartum depression. Previous studies had tracked depression recurrence between 25 and 40 percent.

What's more the researchers also found that prescribing preventive antidepressants for this group of women did not affect the risk for developing postpartum depression. So much for the notion of just prescribing anti-preventive depressants to new moms with a history of depression, as a matter of course.

The only effective predictor for PPD turns out to be the clinical interviews with the women about work activities, insomnia and suicidal thoughts. The UCLA findings strongly suggest that structured interviews about difficulties at work could alert doctors to patients at risk of postpartum depression who might benefit from being referred to a psychiatrist for monitoring after they give birth.

The research has been published in The Journal of Clinical Psychiatry.