The essay was posted in response to the backlash she has received over comments she made about being a working mother.
"A few weeks ago during an interview, I was asked why I have only worked on one film a year since having children. My answer was this: Film work takes one away from home and requires 12-14 hours a day, making it difficult to be the one to make the kids their lunch, drive them to school, and put them to bed," Paltrow wrote in Thursday's message.
"So I have found it easier on my family life to make a film the exception, and my 9-5 job the rule. This somehow was taken to mean I had said a 9-5 job is easier, and a lot of heat was thrown my way, especially by other working mothers who somehow used my out-of-context quote as an opportunity to express feelings (perhaps projected) on the subject. As the mommy wars rage on, I am constantly perplexed and amazed by how little slack we cut each other as women. We see disapproval in the eyes of other mothers when we say how long we breastfed (Too long? Not long enough?), or whether we have decided to go back to work versus stay home. Is it not hard enough to attempt to raise children thoughtfully, while contributing something, or bringing home some (or more) of the bacon? Why do we feel so entitled to opine, often so negatively, on the choices of other women? Perhaps because there is so much pressure to do it all, and do it all well all at the same time (impossible)."
Paltrow, 41, is best known for her work in the films Iron Man, Emma and Shakespeare in Love. She and her soon-to-be-ex-husband, rocker Chris Martin, have a son and daughter together.