* House backs ban on federal funds for abortions

* Measure helps win support from moderate Democrats

(Updates with comments)

By Donna Smith

WASHINGTON, Nov 7 (Reuters) - The U.S. House of Representatives voted on Saturday to tighten a ban against using federal funds to finance abortions under the proposed Democratic healthcare reform legislation.

Opposition Republicans joined forces with anti-abortion Democrats to pass the amendment to the healthcare legislation on a vote of 240-194.

The House approved a sweeping healthcare overhaul on Saturday on a narrow 220-215 vote. The battle over President Barack Obama's top domestic priority now moves to the Senate.

The anti-abortion amendment angered liberal Democrats who support abortion rights, but its passage helped win backing for the legislation from moderate Democrats, many of whom had refused to support the bill without strengthening language that bars using federal subsidies to fund abortions.

"Placing onerous new restrictions on a woman's right to choose sets a terrible precedent and marks a significant step backwards," Democratic Representatives Louise Slaughter and Diana DeGette, co-chairs of the congressional pro-choice caucus, said in a statement.