WASHINGTON — The Federal Reserve’s decision to keep up its stimulus program bolstered the view that a strengthening U.S. economy will drive world growth forward in the coming months.

The Fed’s decision on Wednesday to hold back on cutting its purchases of $85 billion a month in bonds may give a temporary respite to developing country economies, which were roiled by the prospect of a reduction. But the easing is inevitable and analysts see more pain ahead for the emerging markets.

The Fed had been widely expected to begin reducing the extraordinary bond purchases that have poured cash into the economy and supported growth at a time when already low interest rates could not be cut much further, limiting the Fed’s range of monetary policy options to spur sluggish growth.

But the central bank surprised by holding off to ensure the U.S. economy is on a firm enough footing to withstand a pullback.

The ongoing stimulus bodes well for the strength of the U.S. economy but the Fed wants to start unwinding the unconventional stimulus measures and return to normal monetary policy. Central bankers also worry if they do not begin cutting back, cheap and plentiful money could fuel inflation and bubbles in asset markets.

Earlier this month, the International Monetary Fund said it saw the dynamics of global growth shifting, with the U.S. expected to drive expansion in the near term helped by European and Japanese economies recovering from their slump. The forecast was a departure from IMF assessments earlier this year that developing economies would be the drivers of the global economy.

Those emerging economies have been rocked the past few months as anticipation grew for the Fed to begin easing off stimulus. While U.S. interest rates were low and cash was abundant, capital flowed into riskier emerging markets where rates were higher, making investments more lucrative.

The Fed’s warnings since May about the impending pullback in bond buying caused a big shift in those financial flows, sending some of that money back into the lower-risk U.S. market as interest rates rise again and growth prospects improve.