New figures reveal that at least 747 women who were in labour were turned away from the hospital where they were due to give birth because there were not enough staff or beds.
Some women had to travel up to 99 miles to find another hospital which would accept them.
The hospital records were obtained by the Conservatives as part of their election campaign.
They show that in Greater Manchester hospitals closed their doors to women in labour 85 times, sending 329 women on to other units.
In the Norfolk and Norwich university hospitals trust area, some women faced journeys of 99 miles to the next hospital.
The longest time a hospital closed to women in labour was 78 hours, at the Heatherwood and Wexham Park hospitals trust in Berkshire.
The most common reasons for closures were staffing and lack of beds.
Shadow health secretary Andrew Lansley told the Guardian: "It's a shocking situation that mothers are being turned away from their local hospital and are forced to travel great distances under stressful circumstances.
"A Conservative government would halt Labour's forced maternity unit closures, ensure that the number of midwives is increased and enable mothers to have safe access to the local services they need."
That sounds great. I wonder how they're going to pay for it.
Professor Sir Sabaratnam Arulkumaran, president of the Royal College of Obstetricians and Gynaecologists, told the Guardian: "Clearly, it isn't good for a woman who is about to give birth to be turned away from her chosen hospital because it is shut due to capacity problems.
"The possible reasons for the high number of closures last year were the shortage of midwives and the implementation of the European working time directive, which reduced doctors' working hours."
He said the Government needed to employ more senior maternity staff and more midwives as it had promised.
However, a Department of Health spokeswoman told the Guardian: "The NHS delivers hundreds of thousands of babies safely every year and England is one of the safest places in the world to have a baby.
"In a recent Healthcare Commission survey nine out of 10 women were pleased with the maternity care they received. Capacity for maternity and neonatal services has increased and there are now more midwives than ever before."
But it must be terrifying to turn up at hospital about to give birth, only to be sent away. Did this happen to you?
Source: The Guardian