ECG, an established and accurate method of monitoring HR, is rarely used in the delivery room for a number of reasons including difficulty ensuring adhesion to the skin (the baby is wet/covered in vernix) and skin damage in premature babies caused by stripping of the electrodes. Current ECG systems also require 3 electrodes to be positioned which can delay resuscitation further. The usual site for transmission PO is the foot or hand. However, in newborn babies, and particularly those requiring resuscitation when the HR is low, blood flow is reduced so physiological mechanisms preserve brain and heart blood flow at the expense of other less important organs and limbs. As a consequence of this and the choice of wavelengths, it can be more difficult to obtain a reliable HR from POs on the limbs, and they typically obtain an HR after 1-2 minutes.