Inadequate staffing and fears over care quality are driving midwives to leave the NHS.
A study of more than 2,700 midwives found some were working in "dangerous" conditions, having 12-hour shifts with no break and worrying about making "tragic" mistakes.
The poll, for the Royal College of Midwives, found the top reasons for leaving were dissatisfaction with staffing levels and fears over the quality of care available.
An overwhelming workload was also found to be a primary reason for leaving - with some midwives looking after up to 15 mothers and babies at a time.
Midwives also reported not being listened to when they told managers they feared for the safety of mothers and babies, while others experienced bullying from senior staff.
Of those questioned in the poll, 31% were midwives who had already left the profession while 69% intended to leave in the next two years.
When asked to expand on their experiences, one midwife said she was stressed "trying to provide good as well as safe midwifery care despite ridiculously low staffing levels and having to complete endless paperwork just to prove I was there".
Others reported feeling depressed, under-valued and concerned that extreme tiredness might lead to a "tragic mistake".
A midwife who left after 40 years said the "stress of under-staffing and the ever-increasing workload" had left her burnt out.
Another midwife described working 12.5 hours with no breaks while in other cases midwives looked after up to 15 mothers with babies at a time.
Some midwives described in detail "dangerous and "unsafe" working conditions.
One midwife described: "Maternity is the most litigious area in healthcare, yet we cannot actually practice safely and in a way that makes us proud, due to chronic staff shortages and cost-cutting".
Cathy Warwick, chief executive of the RCM, said the findings were "saddening, dispiriting and worrying".
A Department of Health spokesman said: "We want midwives to feel proud of their work and that they have enough time and support to give good care".
They added that the NHS was introducing a £5m campaign to improve the health and well-being of staff.