The Federal Reserve raised interest rates for a 12th straight meeting, taking the cost of borrowing to 4 percent.
In contrast, recent mixed data is clouding the outlook for UK interest rates, which stand at 4.5 percent.
Analysts said there was little fundamental news behind sterling's modest rise against the dollar on Wednesday, which was its first in three sessions.
"The concern for sterling is still that any weakness in the upcoming economic data could lead to talk of rate cuts again," said Chris Gothard, currency analyst at Brown Brothers Harriman.
Sterling was trading at $1.7700 as of 1515 GMT, up around 0.2 percent on the day and a cent above a two-week low of $1.7600 set on Tuesday.
It was also slightly stronger against the euro at 67.95 pence ahead of a policy meeting from the European Central Bank (ECB) on Thursday. The ECB is expected to stick to its line of "strong vigilance" against inflation in its monetary policy statement, possibly paving the way for a rate rise as early as December. Eurozone rates stand at 2.0 percent.