A hospital trust, criticised after the deaths of two babies, has had conditions placed on its registration with an NHS watchdog.
The Care Quality Commission (CQC) said "further urgent improvements" were needed at Milton Keynes Hospital NHS Foundation Trust.
In January this year the CQC said it must employ more permanent midwives and open more maternity beds.
The hospital said it did provide safe and quality maternity services.
Earlier this month, it was announced that an expert team was being sent in to improve the failing maternity unit run by Milton Keynes.
It comes after the trust failed to respond quickly enough to recommendations made in 2008 and again in January this year, following the deaths of two babies in June 2007 and May 2009.
The CQC announced that 64 trusts had been registered without conditions in the first of three waves of registering NHS trusts.
Milton Keynes is one of only two registered with conditions.
Milton Keynes is non-compliant with four of the 16 essential standards.
These include not having enough midwives and not having enough cover at all times to monitor at-risk mothers and babies.
While the trust has an action plan, it does not focus on outcomes for patients or "adequately address medium and long-term safety issues".
Roxy Boyce, CQC regional director, said the trust had been told it must - by law - give women in labour one-to-one support from a midwife.
She said: "The trust has not always responded fast enough to address concerns raised by patients or those raised by the regulator."
Jill Rodney, chief executive of Milton Keynes Hospital NHS Foundation Trust, said: "We would like to reassure local women that our maternity department does provide a safe and quality service.
"Our team has been touched by the number of mothers who have recently contacted us... to tell us about the good experience they had at our unit."
The commission had investigated the unit after the death of Romy Feast in 2007.
She died less than an hour after being delivered by Caesarean section.
Milton Keynes coroner Thomas Osborne found surgery was needed straight away but was delayed by three hours because of "system and communication failures".
The hospital was also criticised over the death of Ebony McCall in May 2009.
"Systems failures" and an overstretched staff contributed to her death, Mr Osborne ruled in December.