In a surprise setback for generally triumphant antiabortion forces, the Senate Appropriations Committee yesterday struck from a money bill a House amendment forbidding use of federal employes' health insurance to pay for abortions.

The motion to strike the language from the Treasury-Post Office money bill was made by Sen. Ted Stevens (R-Alaska) and approved 11 to 8 with the support of six Democrats and five Republicans. Efforts to restore it probably will be made on the Senate floor.

If it stays out of the bill, it could lead to another wrenching fight between House and Senate such as those in past years that held up the HEW money bill for months while the two bodies fought over use of federal money to perform abortions on poor women.

The House has pretty much prevailed in the fight to forbid use of federal money to perform abortions on welfare women. But this year it moved into a new area when it tried to forbid federal employes from using their health insurance to have abortions.

Sen. Richard S. Schweiker (R-Pa.) voted to keep the ban in the bill, saying that if Congress is going to prevent poor women from having abortions it should treat working women the same way. The Senate committee's different attitude yesterday may mean that federal employes have more clout than poor people. Federal employes' insurance was used to pay for about 20,000 abortions last year.