I don't know where they get their 52-41 numbers, but all during the 2006 elections, they were padding the poll numbers by anywhere from 11% to 16% - so I don't believe their numbers.
Other polls taken by legit groups have always had a high number for pro-life than for pro-choice.
Depends on how you ask the question. If the question is 'should first trimester abortions be legal,' it's certainly possible that the spread would be 51-42 in favor of pro abortion.