A coaltiion of women's and religious groups, politicians and population and health experts asked President Carter yesterday to reconsider his opposition to use of Medicaid funds to finance abortions for the poor.

Midge Costanza, assistant to the President for public liaison, told the group at the Executive Office Building that, despite the pressure on Carter, "I don't think the President will change his mind. He's adamant on this issue."

The President has said he opposes use of Medicaid funds for abortions, except in case of rape or incest or to save the life of the pregnant woman, because "there is a moral factor involved."

The Ad Hoc Committee for Women's Health and Reproduction termed that position "shocking and deeply disappointing to millions of Americans" who support equality of opportunity and respect for the moral views of others.

The group asked the President several questions in a prepared statement, including: "Is it moral to implement a government policy that is inherently and admittedly discriminatory?" and "Is it moral for this country to advocate human rights and liberty abroad, while depriving the weakest in our society of their moral and human rights?"

The group criticized the administration for doing little to promote research on safer, more effective birth control methods and for doing "virtually nothing" to educate the public about preventing unwanted pregnancies.

Robin Chandler Duke, chairman of the Draper World Population Fund, heads the Ad Hoc organization. It includes the American Public Health Association, Mexican American Womens National Association, Planned Parenthood, Population Crisis Committee, World Council of Churches, United Methodist Church, American Association of University Women, National Conference of Puerto Rican Women, National Women's Political Caucus, Women's Action Alliance and Alan Guttmacher Institute. Also members are philanthropist Mary Lasker; Arvanne Fraser, coordinator women in development, Agency for International Development; Marvella Bayh, wife of Sen. Birch Bayh (D-Ind.), and Jane Hart, widow of Sen. Philip Hart (D-Mich.).

There is also a group of members of Congress who have asked to meet with the President on the abortion issue this week, before Senate and House conferees try to work out a compromise anti-abortion legislation. The Senate would allow Medicaid funding for "medically necessay" abortions; the House would permit abortions only in specified cases, as to save the life of the woman.

Last week, top-level women presidential appointees and Agency staff members protested Carter's abortion position. They will send a memorandum to the President stating their views this week.

A White House press aide said the President would have no response to either group until he reads their statements.