A third of new mothers are left alone and uninformed after giving birth, the Royal College of Midwives (RCM) says.
A total of 43% of 3,500 women polled had no access to a midwife while on a postnatal ward, while 35% were left alone during and after labour.
Almost a quarter of mothers said they had received insufficient support after leaving hospital, with 24% complaining they had not been visited regularly by midwives while at home.
Despite the problems, 29% of women described their maternity care as "excellent".
RCM general secretary Cathy Warwick said: "The government promised a 'world-class maternity service' for all new mothers.
"This is what mothers and babies have been promised and, quite frankly, what they deserve.
"Local NHS managers may be able to achieve some of the needed changes to improve maternity services, but whilst there are more midwives coming into the system, mums are still concerned about staff shortages."