It is estimated that while more than 80% of peripartum (before childbirth) women may experience some fluctuations in mood in either the antepartum period or postpartum (after childbirth), only 10-20% meet the criteria for an affective disorder.

Prevalence:

Depressive symptoms in pregnancy	25-35 %
Postpartum "blues"	50-85 %
Postpartum depression	10-20 %
Postpartum psychosis	0.1-0.2 %