Hillary Rodham Clinton, former US secretary of?state

Hillary Rodham Clinton said she knows she has a decision to make about running to become the first female US president, and believes "we need to break down that highest, hardest glass ceiling in American politics".

The former secretary of state told People magazine that she wants to enjoy the moment - she's about to become a grandmother - as she considers "what I think is right for me". But she said many US citizens think the nation has "unfinished business" in sending the first woman to the White House.

"I'm certainly in the camp that says we need to break down that highest, hardest glass ceiling in American politics," the former first lady said. "To have a woman president is something I would love to see happen, but I'll just have to make my own decision about what I think is right for me."

The interview was posted a few days before the release of Clinton's new book on her four years as US President Barack Obama's secretary of state. She told People that she remains "concerned about what I see happening in the country and the world". She said she will consider her future in the coming months, with "the extra joy of 'I'm about to become a grandmother.'"

Discussing her health, Clinton said she has no lingering effects from a concussion she suffered in late 2012, saying she dealt with dizziness and double vision.

"Those all dissipated," she said, noting that she uses blood thinners to treat a blood clot that was discovered during her hospitalization after her concussion.

Clinton said that during Obama's 2013 inauguration, she asked US Representative Paul Ryan whether he ever had any concussions from his athletic pursuits. She said the former Republican vice-presidential candidate told her he had "three at least", and one was "really serious." Clinton said Ryan told her he was grateful to his mother for forcing him to rest until it went away.

Ryan spokesman Brian Bolduc said Ryan had spoken to Clinton about his concussions but Ryan said he had two concussions, not three.

In the interview, she described a life partially removed from politics after spending the past two decades in the public eye. She and her husband, former president Bill Clinton, "totally binge-watched" the Netflix political television show House of Cards and she has done water aerobics and yoga in her spare time.

Clinton said she did not make time to read the recent essay written by Monica Lewinsky, saying she had "moved on". Asked whether she regretted calling Lewinsky a "narcissistic loony toon", Clinton said she was unwilling to talk about her husband's extramarital affair in the mid-1990s with the then-White House intern - a scandal that nearly brought down her husband's presidency.