The U.S. currency - which appreciated this year, helped in part by a rally in U.S. Treasury yields - has come under pressure in recent sessions as yields have retreated.
Euro-sterling's downward trajectory stalled somewhat on Thursday after it came close to, but did not breach, the key 0.85 level in the previous session.
Versus the euro, it was down around 0.1% at 85.2 pence per euro.
After rising above $1.42 in February to its highest level against the dollar since April 2018, sterling lost some ground versus the greenback in March.
Expectations that Britain's economy will reopen quickly after its rapid vaccine rollout lifted sterling to $1.42 in February, at the time making it the best performing G10 currency.
The pound has lost over 1% against the dollar this week, as the EU, which is lagging Britain and the United States in rolling out vaccines, considers the measure.
More than 22 million people have had the first dose of a COVID-19 vaccine in the UK. Traders expect the swift inoculation programme will help the economy rebound from its biggest contraction in 300 years.
In early London trading, the pound rose to a two-week high against the euro at 85.57 pence. It was flat at 85.76 pence at 1227 GMT.
US Federal Reserve Chair Jerome Powell failed to soothe investor concerns about a recent surge in borrowing costs as he spoke at a Wall Street Journal forum on Thursday, pushing the safe-haven dollar higher.
Sterling fell to a three-week low against the dollar, briefly dropping below $1.38. It was last down 0.6% at $1.3810.