text: Hillary Clinton  'whooped' for joy at the birth of her granddaughter before she saw Bill becoming tearful in the hospital waiting room, she has revealed. The former Secretary of State gave details of her daughter's pregnancy in a new Epilogue for her memoir, Hard Choices, released just days before she is expected to announce her presidential run. In the new chapter, shared by the Huffington Post on Friday, she suggested that the birth of her granddaughter made her think about the future of all children and had motivated her political plans. She explained how in 2014, she and her husband got the 'wonderful news' that their daughter Chelsea and her investment banker husband Marc Mezvinsky were expecting a baby. Doting: Hillary Clinton, pictured with her husband Bill and their granddaughter Charlotte after her birth last year, has said the baby girl has made her realize she has much more work to do . Hillary Clinton was 'unabashedly giddy' at the news, she said. 'As the summer slipped away, I drove Chelsea crazy checking in practically every hour,' she wrote. 'How are you feeling? Any news from the doctor? When's it going to happen!' But, whereas she and Bill had been disorganized ahead of the birth of Chelsea, their daughter was far calmer and better prepared, she wrote. 'I remember how frazzled [Bill] was when it was finally time to go to the hospital,' she recalled of her own labor. 'Lamaze recommended bringing a small plastic bag of ice to suck on during labor. Bill ended up bringing enough to fill a thirty-nine-gallon garbage bag. It was quite a sight. 'By comparison, Chelsea and Marc were much more organized and prepared.' In September, Chelsea started going into labor in New York City, so they headed to the hospital to greet their first grandchild - Charlotte Clinton Mezvinksy, who was born on September 26. 'Chelsea emerged, exhausted but glowing,' she wrote. 'All our pent up nervous energy burst out in laughter and excited whoops, more like a couple of kids than the newly-minted grandparents we had suddenly become. 'After a while, Bill and I stepped out into the hallway to let them rest. We sat quietly, holding hands, trying to process the rush of emotions. I looked over and saw a tear in Bill's eye.' Calm: In a new chapter of her book, Hillary Clinton said her daughter Chelsea and son-in-law Marc Mezvinksy were far more organized and relaxed about the birth of baby Charlotte than she was about Chelsea . Proud: She revealed that she saw tears in her husband's eyes after the birth of baby Charlotte at Lenox Hill Hospital in New York City, pictured, last September. She is the couple's first granddaughter . She explained that while she had been nervous about giving birth to Chelsea and the impending responsibility, 'as a new grandmother... there is nothing but joy'. 'It's probably the world's best job,' she wrote. 'I love every minute of it.' She added that even though she has a terrible singing voice - so terrible that an 18-month-old Chelsea told her to stop singing to her - she enjoys singing lullabies to baby Charlotte. 'Charlotte has yet to complain,' she wrote. Welcoming her granddaughter has made her want to make the world a better place for Charlotte and other children, she wrote in the epilogue - hinting that she will be back in politics soon. 'Becoming a grandmother has made me think deeply about the responsibility we all share as stewards of the world we inherit and will one day pass on,' she wrote. 'Rather than make me want to slow down, it has spurred me to speed up.' Nervous: She said that before the birth of Chelsea, pictured together in the 1980s, she had been so nervous about being a mother but that now she finds being a grandmother is pure joy . She went on: 'In just a few months, Charlotte had already helped me see the world in new ways. There was so much more to do.' Earlier this week, former President Bill Clinton said his granddaughter has changed his outlook in politics too - although it's had the opposite effect. 'I've told Hillary that I don't think I'm good [at campaigning] anymore because I'm not mad at anybody,' he told Town & Country magazine. 'I'm a grandfather, and I got to see my granddaughter last night, and I can't be mad.' It followed reports that Hillary has rented space for her campaign headquarters in Brooklyn Heights. According to reports on Friday, she will announce her bid to run for president on Sunday before immediately traveling to Iowa and New Hampshire to meet with voters.
target: In the new chapter released on Friday, Clinton shared her experiences as a grandmother and how they had motivated her political plans .
  She recalled how disorganized she had been before the birth of Chelsea, whereas Chelsea had been so composed before becoming a mother .
  The Clintons 'whooped' with delight when Charlotte was born last September and Hillary noticed Bill becoming emotional .
  While she had been nervous about being a mother, being a grandmother is 'pure joy' - and has made her think about all children's futures, she said .
  She is expected to announce her run for president on Sunday .