* U.S. indexes post modest gains, European shares edge lower
* Republicans postpone bill after failing to find votes
* Failure might shift agenda straight to tax reform
* Gold prices gain as dollar steadies (Updates to open of U.S. trading; changes byline, dateline, pvs LONDON)
By Sam Forgione
NEW YORK, March 24 (Reuters) - U.S. shares edged higher and European shares slipped on Friday as investors were on tenterhooks awaiting the outcome of a vote in Washington on healthcare reform, seen as pivotal for U.S. President Donald Trump's pro-growth agenda.
All three major U.S. indexes gained modestly in morning U.S. trading despite uncertainty that Trump and the Republican leaders who crafted the healthcare bill had enough support to pass it, meaning they now risk defeat in their first attempt at major legislation and a key campaign pledge.
Trump warned House Republican lawmakers that he will leave Obamacare in place and move on to tax reform if they do not get behind new healthcare legislation in a vote on Friday.
The back-and-forth over the bill has led to some of the choppiest trading Wall Street has seen since Trump’s election in November. Investors had grown worried that a failure of the legislation would damage prospects for Trump’s pro-growth agenda items – tax reform and stimulus – and earlier this week that led to the biggest daily drop U.S. stocks have seen since the election.
Some of that concern appeared to be ebbing on Friday ahead of the scheduled vote in the House, with some analysts and investors seeing a failure of the bill as a catalyst to bring forward action on tax reform in particular. Despite Friday's gains, the Dow and S&P 500 were still on track to post their first monthly declines since October.
"If this goes on the back burner and they start addressing corporate tax rates or infrastructure, that would be a positive for the market because the administration is not going to look at this and say 'Hey, this thing is going to take a while,'" said Bucky Hellwig, senior vice president at BB&T Wealth Management in Birmingham, Alabama.
MSCI's all-country world equity index was last up 1.43 points, or 0.32 percent, at 448.91.
The Dow Jones Industrial Average was last up 56.96 points, or 0.28 percent, at 20,713.54. The S&P 500 was up 9.6 points, or 0.41 percent, at 2,355.56. The Nasdaq Composite was up 38.98 points, or 0.67 percent, at 5,856.67.
Europe's broad FTSEurofirst 300 index was down 0.12 percent at 1,485.23.
The U.S. dollar index, which measures the greenback against a basket of six major rivals, was little changed at 99.736, but that left it near a roughly seven-week low of 99.547 touched on Wednesday.
That allowed safe-haven gold prices to edge higher. Spot gold prices, which hit a more than three-week high on Thursday of $1,253.12 an ounce, were up 0.12 percent at$1,246.33.
U.S. Treasuries prices were steady ahead of the vote, with benchmark 10-year yields last at 2.411 percent, roughly unchanged from late Thursday's yield.
“This is being seen as a good litmus test of the rest of Trump‘s agenda,” said Gennadiy Goldberg, an interest rate strategist at TD Securities in New York.
Oil prices were flat amid hopes that an OPEC output cut was beginning to balance a long-oversupplied market.
Brent crude was last up 1 cent at $50.57 a barrel. U.S. crude was up 2 cents at $47.72 per barrel. (Additional reporting by Patrick Graham and Libby George in London, Tanya Agrawal in Bengaluru and Karen Brettell In New York; Editing by Nick Zieminski)