The government has ordered special measures be introduced at a maternity unit in north west-London over concerns at the high number of women's deaths.
The maternity unit at Northwick Park is being investigated
The move comes after an investigation at Northwick Park Hospital revealed "serious system failures".
In the past three years 10 women have died at the hospital, which records about 5,000 births a year.
The Healthcare Commission said it would now begin an investigation into each of 10 deaths to rule out any link.
The hospital welcomed the measures which it said would help to "improve staffing levels and increase capacity".
Caesarean deliveries will now be carried out at the private Portland Hospital in central London in order to relieve pressure on maternity services at the unit.
In the UK an average of about one mother in 8,700 dies in childbirth.
Professor Arul Kumaran, from St George's Hospital in south-west London, will also now lead a small team of doctors and midwives at the unit and external clinical support will be provided by other hospitals.
The trust's chief executive Mary Wells said mothers should still be "confident in continuing to use the maternity unit".
The North West London Hospitals NHS Trust asked the commission to start an investigation into its maternity services in August 2004.
They had been working together to tackle system failures at the unit and in December the trust agreed to take urgent action to remedy any problems.
But during an unannounced spot-check, the commission found agreed actions had not been carried out, thus prompting intervention from the Health Secretary John Reid.
Commission chairman Sir Ian Kennedy said: "We found serious problems with these services and no longer had sufficient confidence that the Trust could resolve them without external help."
The Trust has set up an information line - 020 8869 5844 - for women using the hospital's maternity services.