Professor Ed Mitchell
SUDI Academic Expert
Auckland University

Ed Mitchell qualified at St George’s Hospital Medical School in London and has worked in the UK, Zambia and New Zealand.

He was the Cure Kids Professor of Child Health Research at the University of Auckland from 2001 to 2015 and is now a Professorial Research Fellow. He has published over 400 original papers, particularly on the epidemiology of sudden infant death syndrome (SIDS). He was awarded a Doctor of Science for his work on “The Epidemiology and Prevention of SIDS” by the University of London. He has received several awards for his landmark studies of SIDS and in 2009 was made a fellow of the Royal Society of New Zealand.

Professor Ed Mitchell answers questions from the community.

What is about bed sharing that causes SUDI?

We believe the mechanism is accidental suffocation. The nose of the baby is soft and can easily be compressed. Also the jaw can be pushed back and occlude the airway. A healthy baby will arouse (wake up) and wriggle, but if mother has taken drugs or alcohol she won’t be responsive to this. Also if the baby has been exposed to smoking when in the womb, the arousal mechanisms are blunted, and the baby may not wake up.

  • smoking
  • bed sharing
  • cause
Does wearing a smoking jacket prevent the risk for SUDI?

My answer to the question ‘as to whether having a “smoking jacket” would prevent risk’ is no. However, I would state that I am not aware of any study that has looked at smoking jackets in relation to SUDI.

Trying to distinguish between the effect of maternal smoking in pregnancy and the effect of passive or second-hand smoking after birth is difficult, as most mothers who smoke in pregnancy also smoke afterwards. Although many maternal smokers quit when they are know they are pregnant, they will have smoked for several weeks before they realise they are pregnant, and the damage may have been done.

From a biological perspective the damage from tobacco (probably nicotine) is likely to occur in pregnancy. Furthermore, it likely to be early in pregnancy as the fetal brain is very sensitive to toxins, such as nicotine. Currently the leading hypothesis is that smoking causes an arousal defect. This means that a baby isn’t able to respond appropriately to, say, airway obstruction caused by co-sleeping. An appropriate response would be to increase the rate of breathing, start gasping, struggle and wake up. The failure to arousal might lead to death, whereas a baby without an arousal defect, will mostly get themselves out of the life threatening situation.

  • smoking