The march, scheduled to take place in Washington DC on Saturday, aims to bring together people who reject words used by President-elect Donald Trump which they claim has "insulted, demonized, and threatened many of us," according to the organiser's website.
On Monday, the Women's March released a statement on Twitter which said that they had removed a partner - the New Wave Feminists- from their list of supporters because they are pro-life.
The statement reads: "The Women's March's platform is pro-choice and that has been our stance from day one.
"We want to assure all of our partners, as well as participants, that we are pro-choice as clearly stated in our Unity Principles... The anti-choice organization in question is not a partner of the Women's March on Washington.
"We apologise for this error."
Stanton Healthcare, a pro-life pregnancy crisis centre in Idaho, was also removed from the list of partners on Wednesday.
A number of Christian feminists responded with outrage over the statement.
Lila Rose, President of Live Action, tweeted:
I am a pro-life feminist. It's sad @WomensMarch refuses to recognize the millions of women who believe women don't need abortion. https://t.co/hMQw7Q6rwG
— Lila Rose (@LilaGraceRose) January 17, 2017
And Christian author Rachel Held Evans wrote:
@KSPrior @womensmarch Progressives have a chance to build a broader coalition here and they are blowing it.
— Rachel Held Evans (@rachelheldevans) January 17, 2017
More than 200,000 people are expected to take part in the Saturday march which the website claims will be "one of the most intersectional marches in US history".