The charity Mind Cymru are campaigning for a specialist mother and baby mental health unit to be reopened in Wales.
The charity said that mothers living in Wales currently have to travel for at least three hours to England now that the last Welsh unit has closed.
Some 21 women have been identified in the last two years who would have been referred to the unit had it been open.
Senior policy and campaigns officer Rhiannon Hedge said: "With no support here in Wales, mothers are having to be treated many miles away from their families and support networks.
"While community support is important, there are times when specialist in-patient care is necessary and at those times it's simply not appropriate for women to be so far away from their families."