Women who have a baby when they are aged 40 or over are at an increased risk of stillbirth, US researchers say.
Women over 40 should have more checks for stillbirth, the researchers say
Older motherhood can be controversial - as the case of Patricia Rashbrook whose son was born when she was 63 showed.
A UK expert said it may be worth considering introducing more testing for pregnant women over 40.
The Yale University work is being presented to the Maternal-Fetal Medicine Conference being held in San Francisco.
Last year, the number of births among women aged 40 to 44 rose 6% in England and Wales.
Around 10 babies are stillborn each day in the UK. Most stillbirths are unexplained.
Difficulties in previous pregnancies, such as pre eclampsia, problems with the position of the placenta which hamper natural delivery and diabetes can increase the risk.
But the US researchers wanted to see if age alone, rather than a health problem in a previous pregnancy, affected the risk of both stillbirth and the death of a child in the womb for older mothers.
They looked at over 11 million babies born to women aged 15 to 44 between 1995 and 1997.
When maternal complications and congenital abnormalities in the foetus were excluded, six million babies remained.
They then looked at data from the US Centers for Disease Control, which registered the deaths of babies.
They calculated that women aged 40 to 44 had three times the risk of stillbirth than women aged 25 to 29.
The researchers also found that foetal checks at 38 weeks of pregnancy had the greatest impact on reducing stillbirth rates in older women.
These checks include listening to the baby's heart-beat and testing the amniotic fluid to pick up any signs of distress.
The researchers suggest 1,700 such checks would be needed to prevent one stillbirth in women aged 35 to 39, compared with just under 500 tests to prevent a baby born to women aged 40 to 44 dying.
Professor Mert Ozan Bahtiyar, of the department of obstetrics, gynaecology and reproductive sciences at Yale University School of Medicine who led the study, said: "Women expecting babies over 40 should be monitored from 38 weeks onwards.
"Any woman in that situation should not panic but, if they detect decreased foetal movement, they should contact their physician."
Dr Maggie Blott, an obstetrician at University College London Hospital, said the study suggested it might be worth considering screening pregnant women over 40.
"We might have to look at how to provide that service."