8 May 2014 Last updated at 05:05 BST
What's less well known is that 3% of men also suffer from the condition.
Researchers in Birmingham say new dads can find it hard to seek help.
BBC Midlands Today's Kevin Reide spoke to Lee and Becky Plummer at their Telford home.
Latest figures show in the year after their baby is born, 13% of women suffer from post natal depression.