Midwifery services across the UK are not receiving the £330m of funding pledged by the government, it has been claimed.
Health Secretary Alan Johnson pledged the extra money to Primary Care Trusts (PCTs) between 2008 and 2011 to improve maternity care.
He said extra cash would go towards the Maternity Matters strategy, which promises that by the end of next year every woman will receive one-on-one support from a midwife throughout her labour.
But the lives of mothers and babies are being put at risk because government funding is not reaching the departments, according to the midwifes' professional body.
Professor Cathy Warwick, general secretary of the Royal College of Midwives, said some midwifery departments have not received their share of the cash from PCTs, meaning they cannot hire the staff needed to ensure every woman gets the care promised.
She added that in many parts of the country the money had gone to PCTs but had not been released to heads of midwifery.
Professor Warwick said: "On the very busy labour wards that are struggling to cope with the rising birth rate, midwives are having to look after sometimes two or three women in labour and that's when the woman ends up being left alone.