Professor Dan Rurak – Biological Reasons for Stillbirths

Late last year (August 2012), the Ritchie Centre was delighted to have Professor Dan Rurak, all the way from the University of British Columbia in Vancouver, present some very interesting work about possible biological mechanisms for stillbirths, particularly those that occur late in gestation.

Professor Rurak presented data on the oxygen supply and demand of the fetus in the womb. His findings highlighted that the oxygen delivery to the fetus decreases with advancing gestational age due a reduction in its supply. For example, there is a decrease in blood flow/kg of fetal weight from 35 weeks of gestation until term and the increase in uterine blood flow does not keep up with the rapid increases in fetal growth rate. What needs to happen, therefore, is that the fetus must somehow decrease its fetal oxygenation consumption to balance out the reduction in supply. During a normal pregnancy this is achieved by the fetus reducing body movements, such as fetal breathing movements, and the rate of growth of the femur declines with increasing gestation.

The implication of these findings may influence conditions such as pre-emclampsia (hypertension during pregnancy) or post-term pregnancy (where the baby has not been born after 42 weeks which is the normal duration of pregnancy). In these conditions, where there is either a compromise in oxygen or a compromise in the demands of the fetus, there may be a mismatch in the supply and demand of the oxygen and these may play a role in the occurrence of stillbirths.
The Ritchie Centre has certainly been very impressed by Professor Rurak’s work that has been a fascinating look into the highly complicated and regulated process of pregnancy.