From Reuters Health:

Poor sleep after childbirth appears to be increase the risk of postpartum depression, according to findings published in the journal Sleep …

Dr. Dorheim's group studied 2830 women who delivered at Stavanger University Hospital between October 2005 and September 2006.

The women reported that they slept an average of 6.5 hours per night. After adjusting the data for other significant depression risk factors — including previous sleep problems, being a first-time mother, not exclusively breast-feeding, having a young infant or having a male infant, and stressful life events — poor sleep was still associated with depression …

"Women with postpartum depression may also benefit from treatment of sleep problems," she added.

Amen. One of the best "treatments" for postpartum sleep problems is that new moms are allowed to get at least 5 hours of uninterrupted sleep each night. The way we did that was that I would get up with the baby until 1 or 2 in the morning, and then my husband would take over after that. We'd go to bed early, and each of us would get a good solid stretch of sleep. You can also do a one or two nights on/one or two nights off plan. It can really help save your life. Sleep is SO important to mental and physical health, especially when you've just had a baby. Just because you have a newborn doesn't mean you're not allowed to get any sleep.

For more stories on sleep and postpartum depression, click the link.