This short video from the Mayo Clinic talks a bit about the baby blues or postpartum depression. It is reported that about 70% to 80% of women in the US suffer from some form of sadness after birth. The blues can be as little as a couple of minutes each day ranging up to several hours. The condition usually goes away after about two weeks.
Still post postpartum depression can appear in about 10% of mothers. When diagnosed it can be successfully treated through group therapy.
In this video they talk shortly about the the condition and give you better insight into the “baby blues” or postpartum depression.
Further reading: American Journal of Psychiatry