Bauer has begun the search for her replacement.
Miron has held various advertising roles in women's magazines at Bauer Media, previously Emap, in the past 13 years. She took the role of director of women's media, responsible for magazines such as Grazia, Heat, More and Closer, in April 2008.
She has reported to David Davies, managing director of Grazia, Heat and Closer, since sales director Jason Trout left the company in the summer.
A spokesman for Bauer said Miron has played a huge role in "building its market-leading position" in women's magazines among advertising agencies and clients, and Bauer "wishes her every success" with the new consultancy.