At the University of British Columbia, researcher Nichole Fairbrother studied over 300 mothers in Vancouver to assess their mental health throughout pregnancy and after birth. She found some interesting results. These results are what I would have hypothesized as well (& I would like to see more research on a larger scale like this in the future).
The study found that many more mamas had anxiety-type symptoms than those who showed depressive symptoms.
Fairbrother says the focus on postpartum depression is good, but more attention needs to be paid to anxiety.