The current bond-buying programme of $85 billion (£53bn) a month is expected to remain in place, although tomorrow's Federal Reserve meeting will be closely watched for clues about when so-called tapering will start.
In a thin day for corporate news the FTSE-100 Index clung to recent gains, closing 4.5 points higher at 6725.8.
The performance in London consolidated advances seen over previous sessions, with the top flight index at its best level since the end of May. Markets in Germany and France also trod water as they await the verdict from America's central bank.
Alpari market analyst Craig Erlam said: "A large majority of investors were convinced that the Fed would start scaling back its asset purchases in September, something the Fed opted against as the economic data did not support it.
"Since then, the US has narrowly avoided default, while its government shutdown for almost three weeks and the economic data hasn't improved. In fact, it's probably deteriorated slightly, so the Fed can't possibly consider tapering this month."
Sterling lost ground on the currency markets as disappointing retail figures from the CBI showed sales volumes stagnated this month, led by falls from supermarkets.
While retailers were optimistic about a sales pick-up next month, economists said warmer-than-expected weather may have dampened sales of winter clothing in October.
The pound was down against the dollar to 1.61 and broadly flat against the euro at 1.17.
Outsourcing firm G4S ended the day down 0.5% despite confirming recent market speculation that it had received an offer worth £1.55 billion for its cash transportation business.
G4S called the approach from private equity firm Charterhouse as "highly opportunistic" and its shares closed down 1.3p at 257.2p.
Generator firm Aggreko achieved the biggest rise in the FTSE-100 after it said its power projects arm - which builds and runs temporary power plants for miners and governments - has quoted for a record level of business over the past six months.
Shares in the group have suffered over the past year but Aggreko reassured investors, saying it is on course to meet pre-tax profits expectations for 2013. The Glasgow-based group surged 6% or 91p to 1608p.
Other big risers on the FTSE-100 were Randgold Resources 212p higher to 4851p, AstraZeneca 52.5p firmer to 3301p and Whitbread 50p stronger to 3422p.
The biggest fallers on the FTSE-100 were Intercontinental Hotels 42p weaker to 1823p, Tullow down 21.5p to 957p, easyJet 29p lower to 1300p and GKN down 8.1p to 364.1p.