The quality of care given to women during pregnancy and birth is "just not good enough" in too many cases, the chief inspector of hospitals has said.
Professor Sir Mike Richards said some women had "truly shocking" experiences at a time that should be the most joyous in a woman's life.
He was speaking as new figures showed a quarter (25%) of women are left alone during labour and birth when they are feeling anxious, up on 22% in 2010.
The Care Quality Commission (CQC) poll of more than 23,000 women across England also found o ne in five (19%) women felt their concerns during labour and birth were not taken seriously.
Some 13% of women were left alone and worried during early labour, 9% during later stages, 2% during the birth and 9% were left alone and worried just after the birth.
The survey showed improvements across many areas of ante-natal and post-natal care but overall 39% had raised concerns about their care during labour and birth.
Some women were told to stay at home for too long, and ended up rushing to hospital at the last minute, giving birth within minutes of arrival.
Once babies had been born, 61% of women felt they were definitely given enough information about their own recovery after the birth, an increase from 42% in 2010.
Nevertheless, some women said they had terrible experiences.
One said: "In the ward, night staff were very rude. They didn't help me at all. I had an emergency C-section and asked a night staff (midwife) to bring me the formula milk, and her answer was 'go and take it yourself'.
"My baby was crying and she didn't help me."
Another said: "After my baby was born, I was disgusted with the paediatrician. She got the wrong patient so nearly gave me medication that I didn't need and gave my baby a blood test that wasn't needed as she got the wrong baby.
"And on my notes, she wrote that I had a baby boy, when I had a girl. I did file a complaint but never heard anything back."
Just over half (52%) of women felt that toilets were very clean, over a third (38%) fairly clean and almost a tenth (9%) not very or not at all clean.
Of more than 1,100 women who wrote comments about feeding their babies, 41% said they felt inadequately supported to breastfeed or felt information was poor.
On home visits after the birth, 16% of women said they were upset that postnatal visits were frequently cancelled or that midwives did not show up.
On the specific question of being treated with kindness and understanding after the birth, 66% said they were always treated in this way - an increase from 63% in 2010.
Overall, 78% of women said they had confidence in the midwives caring for them - up from 73% in 2010.
Three-quarters of women also said they were always involved in decisions about their care - up on the previous survey.
Prof Richards said: 'I'm encouraged there are improvements but in too many cases, the quality of care delivered is just not good enough.
"Women and their partners are being left alone when it worries them, toilets and wards are described as unclean, and some women are not given the pain relief they had expected or planned to use in their birth plan.
"Further findings of note include those about continuity of care, these suggest to me that women do not mind seeing different midwives if the information and messages they receive is consistent.
"Feedback in the comments shows at times a truly shocking picture of experiences that should be the most joyous time in a woman's life, not the most frightening."
Cathy Warwick, the Royal College of Midwives' chief executive, said: "We welcome evidence of improvements in women's experience of maternity care since 2010, but there are worrying findings, too.
"It is sad to see that in three years the NHS has not improved in terms of women seeing the same midwife during their care, which often means women have to repeat their histories over and over again."
She said the union's latest estimate is that the NHS in England is short of 4,800 midwives.
"We are seeing some action to bring this shortage down, but those efforts need to be redoubled if we are to see fewer women have a negative experience of what should be amongst the happiest moments of their lives."
Shadow public health minister Luciana Berger said: "This survey reveals how new mums are being badly let down and standards have slipped back in recent years.
"Ministers must explain why women feel that their concerns weren't taken seriously and a growing number were left alone during labour.
"Maternity units must be adequately staffed. At the election, David Cameron promised thousands more midwives but he's failing to deliver them."
Health minister Dr Dan Poulter welcomed improvements but said in some cases new mums are not getting good enough care.
He added: "There are now over 1,200 more midwives working in the NHS as well as a record 5,000 more in training who will qualify in the next three years. Last year I announced a £25 million fund to pay for improvements to over 100 maternity wards and birthing units."