A new study suggests that epidurals can drastically reduce the risk of PPD. The study is flawed, but does manage to show that PPD is highly complex with multiple etiologies.
Sadly it seems far too many people - mothers, doctors, midwives, etc. - either don't understand the averages of labouring and birthing times or downright ignore them. When it comes to birth this can mean far too many women being diagnosed with "failure to progress" and facing numerous (unnecessary) interventions.
My view in a nutshell: The development of the epidural was a great scientific discovery that has the power to help women who NEED it in labor. It has its place in the world of childbearing, but it has also been VASTLY overused and many of those who opt for it have no idea what it is that they’re choosing to do.