Women about to give birth are being turned away from their local Mid Sussex maternity unit more often than almost anywhere else in England.

The unit at the Princess Royal Hospital, Haywards Heath, was closed to new admissions on 13 days in the last year.

The number of hours the unit was closed ranged from two to six hours at a time.

And the hospital has the fifth highest closure rate in England and Wales, according to figures published today in The Times Good Birth Guide.

The guide is compiled by medical researchers Dr Foster, which has been investigating all hospital maternity units.

The Princess Royal is one of three Sussex hospitals to feature in the top 20 hospitals to have closed most often.

Brighton's Royal Sussex County Hospital is fourth on the list. It closed 16 times in the last year.

Worthing Hospital, which closed four times, is ranked equal eleventh with units in London and Wales.

All three hospitals say they are constantly busy and staff shortages mean midwives are working at full stretch.

This means there are occasions when the unit can no longer take in new patients because midwives are dealing with several births already.

Hospitals admit it can be upsetting for women who have been getting regular antenatal care from a hospital to be sent elsewhere when they go into labour. But they insist it is only done as a last resort.

A spokesman for Princess Royal said: "The unit is a very busy one and on the occasions staff go off sick it adds to the pressure.

"If the unit is full, in terms of safety for both the mother and the baby we would advise the patient to go to another maternity unit."

Meanwhile, a spokes-man for Royal Sussex said: "We closed the maternity unit to new admissions on 16 occasions during the year in question.

"Some of these were for as little as four hours. The total period over the whole year was 135 hours - in other words, we were open for 98.5 per cent of the year.

"The unit is only ever closed if the senior midwife believes client safety would be compromised if it was left open.

"It is closed when the ratio of mums-to-be to midwives causes concern.

Both the Princess Royal and Royal Sussex County Hospital are considering putting together a business case to apply for more money to recruit extra midwives to help cope with demand.