It comes before the Royal College of Obstetricians and Gynaecologists (RCOG) hold a secret vote on whether to relax the laws governing the procedure on Friday.
A group of 650 medics reportedly signed a letter to Professor Lesley Regan, president of the RCOG objecting to her view that terminations should be treated like other medical procedures.
Robert Colquhoun from the Christian pro-life group 40 Days for Life told Premier's News Hour its important resistance is voiced.
He said: "I think it's really important for many of the Royal Colleges to know that there many Christian healthcare professionals who are opposed to the decriminalising of abortion.
"I believe that it will be a detrimental development in the provision of abortion in this country."
The College could decide to pressure the Government to relax the law.
While it's unclear what the impact of the letter will be, Chief Executive of the Christian Medical Fellowship, Dr Peter Saunders told Premier it sends a strong message to the College nonetheless.
He said: "I think it's hugely significant given that the signatures were gathered in just 24 hours or so...I hope the RCOG does listen to this and at very least, carries out a ballot of its whole membership."
According to the Daily Mail, while the RCOG represents 6,000 senior doctors in England specialising in childbirth and women's health, only 33 members of the body's council will take part in the ballot.
The medics opposed to abortion on demand urged in their letter for the president of the RCOG to hold a ballot of all 6,000 members.
It stated: "If these measures were to be implemented, it would mean the introduction of abortion for any reason, to at least 28 weeks and possibly up to birth.
"It is completely unacceptable that all members of the RCOG have not been given the opportunity to vote on this significant change in policy and you have refused to release the wording of the motion until after the general council have voted on this motion. As doctors and medical students, we object to this new extreme position being forced upon members of the RCOG."
The ballot will decide whether the College should formally back 'total decriminalisation' allowing consent from just one professional.
It's likely a vote in favour would put pressure on the Government to overhaul the law.
Listen to Robert Colquhoun 40 Days for Life speaking with Premier's Eno Adeogun: