The lives of new mothers and babies are at risk from poor conditions in some maternity wards, a report has warned.
Standards varied greatly in different trusts, the report found
The Healthcare Commission highlighted overcrowding, dirty toilets, a shortage of midwives and inadequate organisation after investigations at three units.
Health Minister Liam Bryne admitted services were "not yet good enough" and said an action plan was being drawn up.
The commission blamed bad management for the problems. It is due to publish a broader report on the NHS on Monday.
Northwick Park, north London: 10 women died during or after birth over two years
New Cross Hospital, Wolverhampton: A review of 20 deaths between 2001 and 2003 found that half might have lived with better care
Ashford and St Peter's NHS Trust, Surrey: "Feuding" between consultants was jeopardising patient care
The investigations - at three units that have suffered high mortality rates in the last two years - also found doctors who did not explain what was happening to patients, and staff too busy to advise on feeding and bathing of new babies.
Sir Ian Kennedy, who chaired the report, called on NHS trusts in England and Wales to review their maternity services because of huge differences between the best and worst.
He blamed a lack of effective leadership and management in units which were failing to achieve high standards. Staff training and the ability to work in teams was also lacking.
"I find it surprising that a service like the NHS, with so many dedicated people working in it, can have pockets of really poor practice, where we have not learned from the wisdom and knowledge and experience that has been put around for a long time as to how to deliver babies in a safe manner, and how to look after mothers.
"We are still not doing it as well as we should, and it is a matter that we need to get a grip on."
The majority of the 650,000-plus births every year in the UK take place in NHS hospitals.
Mr Byrne said: "We welcome his acknowledgement that giving birth is safer now than ever before and that very few babies or mothers die.
"However services are not yet good enough to meet the needs of all women and babies, wherever they live and whoever they are, and that is why the government continues in reforming, as well as investing in, maternity services in the UK."
Shadow health secretary Andrew Lansley said: "These findings from the Healthcare Commission are deeply worrying.
"They show that despite increasing resources for the NHS, a lack of genuine reform means resources are wasted and services are not held accountable for the standards they meet and to the wishes of patients."
Mikaela Morris, a senior midwife at St Peter's Hospital in Surrey, which was investigated by the commission, said her unit had suffered from a shortage of midwives.
At one stage they were operating with about 70 when they needed 100.
"It is a big national problem. We have not had enough people wanting to become midwives."
But she urged people to join the profession, saying while it could have "tragic moments" it was "very very rewarding".
The report into the broader NHS is expected to show that staff shortages, aged buildings, poor training and weak management are hitting standards.