What causes a baby to be stillborn?

A stillbirth is the death of a baby in utero at any time during pregnancy, after the 24th week. The latest figures for the number of babies who are stillborn every year are for 2008.

Common direct causes of stillbirth include:

  • the mother haemorrhaging either before or during labour
  • when the baby has a congenital abnormality 
  • when there is an infection, such as Group B Strep
  • as a result of pre-eclampsia


Intrapartum deaths

Around 500 babies die every year in the UK as a result of 'events during labour' when the baby does not get enough oxygen. These are clearly some of the most avoidable deaths of all since, if the baby's labour had been managed in a different way, the baby might have lived.


Unexplained stillbirths

At least 50% of all stillbirths are 'unexplained'. Further investigation, however, suggests that other 'associated conditions and factors' have contributed to the baby's death.  These may not themselves be direct causes of death, but they play their part. Each of these conditions and factors listed contributes to roughly ten per cent of all stillbirths every year.

  • placental function, when the placenta ceases to function adequately
  • intrauterine growth restriction (IUGR) when the baby does not reach its growth potential
  • ‘mechanical’ causes (such as cord knots, uterine rupture, and breech presentation)


This leaves around 25%, one in four stillbirths, as still 'unexplained'. It may be that only further research will help us understand why a seemingly perfecty healthy baby dies in utero. It may be that with further investigation we are able to work out which of these deaths was in fact avoidable, if the mother and baby had received better care.


Risk factors for stillbirth 

One in 200 births ends in a stillbirth. But there are also factors which increase this risk. Stillbirths are more frequent among the following women:

  • twin or multiple pregnancies
  • older mothers, ie. over the age of 35
  • teenage mothers
  • women with specific medical conditions, especially diabetes, hypertension and thrombophilia
  • women with a past obstetric history of complications
  • women who smoke
  • women who are obese
  • women living in areas of social deprivation
  • women from ethnic minority groups