By Avril Ormsby
London - Nearly half of NHS maternity units had to turn away women in labour last year because they were full, figures showed on Thursday.
Furthermore, a shortage of facilities or staff led to almost one in 10 of these trusts closing more than 10 times.
One trust closed 28 times, while another was forced to shut its doors 39 times.
The figures, collected by the Conservative Party under the Freedom of Information Act, showed large maternity units were more likely to be forced to close than smaller ones.
Shadow Health Secretary Andrew Lansley blamed the government's policy of closing small maternity units in favour of larger ones for the situation, arguing it "flew in the face of common sense".
"Women don't want to have to travel miles to give birth," he said.
"And they certainly don't want to have to travel even further because they're turned away by the hospital of their choice."
The Royal College of Obstetricians and Gynaecologists (RCOG) said 400 extra consultants are needed in England and Wales.
Maternity units are being put under additional pressure because of the growing birth rate, increased numbers of obese women giving birth - who require extra care - and the rise in the number of women in their 40s becoming pregnant.
Richard Warren, RCOG honorary secretary, said: "It is imperative to ensure that maternity units are appropriately staffed and resourced to meet the demands that the service requires."
The Royal College of Midwives said: "The vast majority of women do not need medical intervention, and midwife led services in smaller units or at home may be the best option for them."
A spokesperson for the department of health said: "It is difficult to precisely predict when a mother will go into labour and sometimes, at times of peak demand, maternity units do temporarily divert women to nearby facilities.
"When this does happen it is often only for a few hours and to ensure mother and baby can receive the best care possible."
Of the 147 NHS Trusts that provide maternity services, 103 provided figures.
Of these, 42 percent reported having closed or having been forced to divert women to another site at least once last year because of capacity problems.