An unborn baby died because its mother had gum disease, it has been reported.
Pregnant women are now being warned about the dangers of poor dental hygiene.
It is very rare for something like this to happen - this is thought to be the first time oral bacteria was responsible for the death of a baby which had nearly reached full term.
The case was revealed in a study published in the Obstetrics and Gynaecology journal.
A 35-year-old woman had the common gum disease gingivitis.
Her baby was stillborn at 39 weeks and doctors found they could trace the oral bacteria in the mum's mouth to bacteria which was found in the baby's bloodstream, lungs and stomach.
Scientists think that any disruption to the amniotic fluid which surrounds the baby in the womb could be a risk to the mother and baby and this could be what happened.
Dr Nigel Carter, chief executive of the British Dental Health Foundation, told the Mail: "This case has shown that improving oral healthcare among pregnant women can have a significant impact on an unborn baby.
"If you are pregnant, it really is vital to take extra care of your mouth. NHS treatment is free for expectant mothers up until their child's first birthday."
The mother in this case was given preventative treatment and later had a healthy baby boy after a second pregnancy.
It does make sense to encourage pregnant women to get dental treatment - especially as it is free on the NHS if you are expecting a baby.
However gum disease is very common during pregnancy and cases like this are very rare so if you do get it, don't panic - just seek treatment.
Source: Daily Mail