She had arrived at the Capitol on an ethics reform platform after defeating the incumbent Republican in the primary and a former two-term Democratic governor in the general election. Her growing reputation as a maverick for bucking her party's establishment and Alaska's powerful oil industry quickly gained her a national reputation.
Now, she said, she is trying to balance caring for her special needs child and running the nation's largest state.
The doctor's announcement in December, when Palin was four months pregnant, presented her with a possible life- and career-changing development.
"I've never had problems with my other pregnancies, so I was shocked," said Palin, who has four other children. "It took a while to open up the book that the doctor gave me about children with Down syndrome, and a while to log on to the website and start reading facts about the situation."
The 44-year-old governor waited a few days before telling her husband, Todd, who was out of town, so she could understand what was ahead for them.
Once her husband got the news, he told her: "We shouldn't be asking 'Why us?' We should be saying 'Well, why not us?' "
There was never any doubt the Palins would have the child, and on April 18 she gave birth to Trig Paxon Van Palin.
"We've both been very vocal about being prolife," Palin said. "We understand that every innocent life has wonderful potential."
Down syndrome is caused by the presence of an extra chromosome in the fetus's cells. It's a genetic abnormality that impedes physical, intellectual, and language development.
The mother's age is a large factor in the chances of having a Down syndrome child. Once a woman turns 40, the chances of having a Down syndrome child is 1 out of 100, according to the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
During her first year in office, Palin distanced herself from the old guard, powerful Republicans in the state GOP, even calling on tightlipped, veteran US Senator Ted Stevens to explain to Alaskans why he was being investigated by federal authorities.
She asked Alaska's congressional delegation to be more selective in seeking earmarks after Alaska's "Bridge to Nowhere" became a national symbol of pork-barrel spending.