It was ultimately fatigue that best predicted which women would develop postpartum depression.

For these women, the constant fatigue came first, and depression followed.

One of the problems with postpartum depression is that women usually aren't diagnosed until the disease is already established. If a woman's health care provider knew early on that a patient was slipping down this slope, he or she could intervene. It may not take much to screen for it, either - the questions in the fatigue test that we used took about two to three minutes to answer.

The biggest problem that women have is being ambivalent about their own power, ... We should be comfortable with the idea of wielding power. We shouldn't feel that it detracts from our femininity.

When you think about it, it makes intuitive sense, when you consider the hallmark signs of depression - sadness, fatigue, lack of interest in things you used to like. When kids are having a tough time with peers, and struggling with depression, then this can translate to reduced rates of physical activity.

All mothers are tired right after having a baby - it helps them get the rest that they needs to recover and heal from the physical and mental stressors of childbirth. But for most women, fatigue steadily fades within the first two weeks of giving birth.