Anne o'hare mccormick was a pioneering woman in the field of:

Anne o'hare mccormick was a pioneering woman in the field of reporting journalism.

At the time (beginning of the 20th century), reporting was primarily done by men, so when Anne O'Hare McCormick appeared, she was the first one to do so. In fact, she also got a Pulitzer Prize for correspondence in 1937, the first woman to achieve that.