A Maryland antiabortion group's drive for a statewide referendum to severely restrict the use of state Medicaid funds for abortions was halted - at least temporarily - yesterday by a Montgomery County judge.

Circuit Court Judge Joseph M. Mathias ruled that the guidelines for state abortion funding are not a proper subject for referendum under the Maryland Constitution.

Leaders of the group, Stop Taxes for Abortion, said they had collected more than 53,000 signatures on petitions seeking the referendum vote. They said they would "most likely" appeal Mathias' ruling.

The Stop Taxes group would like the voters to reject guidelines set forth in the state budget that allow Medicaid abortions for poor women in a broad range of circumstances.

One of the guidelines allows a Medicaid abortion if a doctor certifies that the mother's health would be harmed by a continued preganancy. The definition of "health" - physical, emotional or mental - is left up to the doctor.

The group would prefer to leave standing only one guideline that allows a Medicaid abortion only when a continued pregnancy "is likely to result" in the mother's death.

Last May, after the group's petition drive began, Maryland Attorney General Francis (Bill) Burch asserted that the guidelines as part of the state budget, are not subject to referendum. The antiabortion group sued to overturn his legal opinion, but Mathias ruled against them.