Sixty-three percent of Americans would rather not see the US Supreme Court overturn its historic 1973 ruling on abortion, according to a Pew Research Center opinion poll released Wednesday.

Only 29 percent want to see the Roe vs Wade decision upended, according to the poll released six days before its the 40th anniversary, said Pew in a statement.

"These opinions are little changed from surveys conducted 10 and 20 years ago," the research institute said.

Abortion remains a hot-button issue in the United States, with pro-life supporters keeping up their campaign to make it difficult if not illegal for a woman to choose to terminate a pregnancy.

Fifty-three percent of the 1,502 adults contacted by telephone by Pew's pollsters on January 9-13 agreed that abortion "is not that important compared to other issues," up from 48 percent in 2009 and 32 percent in 2006.

Support for overturning Roe vs Wade was strongest among white evangelical Protestants (54 percent), while 55 percent of all Catholics were opposed despite the Vatican's hardline stance against abortion.

Pew also found that awareness of Roe vs Wade was much higher among those aged 50 to 64 (74 percent) than it was among Americans younger than 30 (44 percent). There was no significant gender gap in the results.

Full results of the survey appear on Pew's website (www.pewforum.org).