At least once, every day, a baby who has started the labour process in apparently good health, dies.
By Clare Murphy
BBC News health reporter
Some bereaved parents are not being offered postmortems
There are 500 cases of these so-called intrapartum-related deaths in the UK annually, a figure which has remained stubbornly static for the past five years.
While more and more is known about the reasons why babies die, mystery still surrounds the deaths of these particular infants.
Whether it is clinical negligence on a busy maternity ward, biological factors, or a combination of both, doctors say the information they need to pin down where it all went wrong is too often lacking.
The Alder Hey scandal of the 1990s, in which organs were systematically stripped from the bodies of dead babies, shook parents' confidence in the postmortem process and led to a new, more complicated system of requiring that "informed consent" be obtained for an autopsy.
A post-mortem is now carried out in only 40% of late foetal, stillborn and neo-natal deaths. Many parents refuse, and many medical staff no longer ask.
And this, according to the body which investigates infant deaths, CEMACH, is taking its toll on establishing why certain babies die - and crucially, working out what can be done to prevent it.
Losing a child in this way is very rare indeed: the risk for mothers carrying babies of healthy weight is 0.3 in 1,000 births. The usual cause of death of asphyxia, but it is the events leading up to this which raise the questions.
It is not a new concern: in the early 1990s, the problem was examined in great detail and panels of midwives and doctors were set up to assess where human error and poor care of mothers had contributed to particular deaths.
As well as calls to sharpen communication between medical staff and improve the ability to diagnose and respond to a problem during the labour period, there was a particular recommendation for all staff to be properly trained in the interpretation of the foetal heart rate monitor.
However at the level of statistics, none of this seems to have had much of an impact - although it has been suggested that clinicians are dealing with increasingly risky births from ethnic minority, obese and older mothers, which might have pushed the death rate up further, were it not for the better training.
But clues such as whether an infection for instance contributed to an infant's death continue to elude those researching the problem.
"We want to investigate every infant death because that is ultimately the way to reduce them," says Richard Congdon, chief executive of the Confidential Enquiry into Maternal and Child Health.
"But we need postmortem information. We really need to encourage parents and persuade them to see postmortems as a benefit for themselves and for society more widely."
Not on offer
At the same time, research suggests that at least 20% of maternity workers are failing to seek permission for a postmortem from parents.
The president-elect of the Royal College of Obstetricians and Gynaecologists says he wants to see an increase in the number of bereavement-trained midwives who have the time to establish a rapport with parents who have just lost a child.
"The postmortem issue is best dealt with by a midwife who is specially trained to spend time with bereaved parents and explain to them the benefits of a postmortem," says Professor Sabaratnam Arulkumaran. "We need two or three per labour ward. At present, some have none."
But he added: "If we really want to see an decrease in infant deaths, we need to increase the number of staff on the ward in general - both at the midwife and consultant level. That's the bottom line."
The other issue which puts parents off a postmortem is the lack of paediatric pathologists, and the lengthy wait for results which may follow, according to the stillbirth and neonatal death support charity Sands.
"Parents are told it could be six, eight, or even 12 weeks," says Katie Duff. "And that is a long and difficult time to wait to hold a funeral."
Ms Duff, whose son was stillborn, did ask for a postmortem to be carried out because "personally, it was important to us to know".
"It's an incredibly individual choice. Some people just cannot hand over their child in the 12 to 24 hours after death in which they are being asked to make a decision. And they may just not agree with it.
"But what's crucial is that parents have the choice. While some parents don't want to know, others really need to, and they must be offered the opportunity to find out."