The rate of stillbirths in England is twice as high among the least well off as it is among the most affluent, shows research published in the online journal BMJ Open.
What is more, this inequality gap is evident across all causes of stillbirth, and has not changed in eight years, the findings show.
The authors assessed the number of singleton stillbirths occurring in England between 2000 to 2007, inclusive. They looked in particular at the specific causes of stillbirth per 10,000 births, in light of deprivation levels and year of birth.
Deprivation was measured at area level, using the UK index of multiple deprivation, and the most deprived 10ths were compared with the least deprived, to assess the extent of any inequality gap.
For every 10,000 births during the eight year period, 44 were stillborn babies, a rate that remained constant throughout.
Rates were twice as high among the most deprived 10th of England as they were among the least deprived - a disparity that remained constant throughout the study period.
This inequality gap was evident for all specific causes other than mechanical events, such as breech presentation, with the widest gap of all seen for bleeding before birth (antepartum haemorrhage).
Women living in the most deprived 10th of England were three times as likely to give birth to a stillborn baby following a bleed before their due date (antepartum haemorrhage), as those living in the least deprived 10th.
Risk factors for this condition include previous pregnancies, several pregnancies close together, smoking, and being at the extreme ends of the reproductive age spectrum, say the authors.
Similarly, stillbirths attributable to congenital abnormalities were nearly three times more likely among women from the areas of greatest deprivation.
Over half of stillbirths (59%) were deaths in the womb of unknown cause, and these accounted for around half of the gap in stillbirth rates between the least and most deprived areas, the findings showed.
Despite improvements in healthcare in developed nations, stillbirth remains relatively common, and the UK has one of the highest rates, say the authors, who add that their findings confirm previous trends.
"If the stillbirth rates seen in the least deprived areas were seen throughout the population, there would be a third fewer stillbirths in England, nearly 900 fewer every year," they conclude.
The evidence from other high income countries, where the rate has fallen, suggests that there are modifiable factors, which can be addressed, they add.