Parenting website Mumsnet has published statistics it says show the treatment and support women receive fails to meet their needs or measure up to official national guidelines.
The survey of 1065 women who had miscarried found 46% of them had to wait over 24 hours for a scan to determine if their baby was still alive, with 18% waiting longer than three days.
It found 47% of the women were treated alongside women with ongoing pregnancies, and 58% of women wanted counselling, but only 12% were offered it.
A Mumsnet user said: "I had to wait six months to get counselling and lost six months of my life as I was not coping with the loss."
Mumsnet also found 56% of the women surveyed wanted further medical care, but only 26% were offered it.
Only 23% spoke of their experience to friends, and only 13% told wider family.
In 2012, guidance on the management of miscarriage stated miscarrying at home would be the default clinical response for women undergoing miscarriage before the 13th week of pregnancy, but today's results show this is leaving women without the support they need.
Of women who miscarried at home following a scan, 15% felt they had the right support, information and pain relief to manage.
Justine Roberts, Mumsnet founder, said: "There's no escaping the pain of a miscarriage, but for this to be compounded by lack of treatment, pain relief, good care or just plain human kindness is unacceptable."