“...the big increases in heart and blood volumes that occur by the 12th week of pregnancy should have the same effect as 'blood doping'. This partially explains the outstanding performances of several female athletes from Eastern bloc countries who were at this stage of pregnancy when they competed in the 1976 Olympics.”
James F. Clapp III, Exercising Through Your Pregnancy“The traditional approach to an unknown risk is avoidance.”
James F. Clapp III, Exercising Through Your Pregnancy