Babies may have died unnecessarily because midwives in understaffed services are failing to spot early warning signals in pregnant women, researchers have said.
The West Midlands Perinatal Institute studied the deaths of 94 babies in the region during 2008-9.
Thirty-five deaths might have been avoided if care was better, it said.
The Department of Health said there were now clear plans in place to improve standards.
It added that these plans at the West Midlands NHS were to "reduce preventable deaths", and that "it is important that these are implemented and make a real difference to maternity services in the region."
Five primary care trusts in the West Midlands commissioned the research into the deaths of babies in six maternity units during 2008-9. Around one in every 100 babies dies in the perinatal period, during birth or their first week of life.
An independent panel of midwives, obstetricians and public health specialists examined these cases in detail for the West Midlands Perinatal Institute. Their report found there were common themes in the 35 deaths where there was substandard care.
These included "apparently hurried and incomplete assessments" of pregnant women by community midwives.
The report says this started a chain of events which resulted in a failure to recognise the risk to the baby and the quality of care the women then received.
Professor Jason Gardosi, director of the West Midlands Perinatal Institute said: "It stuck out time and time again that the care at the early 'booking' visit, which is a very important part of antenatal care, was done but not of the quality that you would expect."
He added: "In many instances this led to series of errors and ultimately to perinatal loss."
'Overstretched and understaffed'
The report also identified "an apparent lack of attention to detail" by maternity staff.
Examples of this included failing to act on risk factors even when they were picked up and a failure to inform mothers when they detected warning signs such as decreased foetal movements.
The most likely explanation for these mistakes being made was "distracted or overworked staff, especially in the community", it said.
The institute also conducted a survey of 278 community midwives in the maternity units where the deaths occurred.
It found that on average the midwives had a case load that was 50% higher than the national recommendation.
Having examined the case notes for all of the deaths, Professor Gardosi said the independent panel concluded the reason for the poor quality of care "was that it was an overstretched and often understaffed service trying to do the best it can".
The report says more work needs to be done on improving outcomes for pregnant women, "which will require appropriate staffing" so that "perinatal deaths are not just designated avoidable but actually avoided".
Belinda Phipps, chief executive of the National Childbirth Trust, said: "This is further evidence that overstretched maternity services and insufficient numbers of community midwives have a real and devastating effect on families.
"It is heartbreaking enough for a parent to lose a child - even more so when they learn their baby's death might have been prevented.
"It is imperative that lessons are learned so more parents' lives are not torn apart."