WASHINGTON -- Illinois Sen. Tammy Duckworth made history on Thursday as she became the first senator to cast a vote on the Senate floor with her newborn by her side.
Senate lawmakers narrowly voted, 50 to 49, to confirm GOP Rep. James Bridenstine to be the next NASA administrator. Duckworth voted against Bridenstine.
"It feels great," Duckworth told reporters as she entered the Capitol. "It is about time, huh?"
She also thanked colleagues for passing the rule change.
"I think it's historic, I think it's amazing," Duckworth said.
The vote comes one day after the Senate changed longstanding rules to allow newborns onto the Senate floor during votes for the first time. The rule change, voted through by unanimous consent, was done to accommodate senators with newborn babies, allowing them now to be able to bring a child under 1 year old onto the Senate floor and breastfeed them during votes.
Duckworth, who is taking her unofficial maternity leave in Washington, DC, spearheaded the push for the rule change. She gave birth to her second child, Maile, 10 days ago.
Earlier on Thursday, the lawmaker tweeted: "May have to vote today. Maile's outfit is prepped. Made sure she has a jacket so she doesn't violate the Senate floor dress code requiring blazers. Not sure what the policy is on duckling onesies but I think we're ready."
The social media post was accompanied by a photo of the potential outfit. Duckworth's dress code joke referred to Capitol Hill's previous rule, which required women -- reporters and lawmakers -- to wear dresses and blouses with sleeves if they want to enter certain areas.
Speaker Paul Ryan announced last year he would change the dress code after a reporter was denied access to a room because she had on a sleeveless dress. Ryan's press secretary AshLee Strong tweeted a response to Duckworth on Thursday: "Senator, It took some drama but Maile and her sleeveless self are welcome on the House floor!"
Late Wednesday night, fellow Illinois Senator Dick Durbin welcomed the newborn to Capitol Hill.
"I think it will do us good in the United States Senate every once in a while to see a pacifier next to the antique inkwells on our desk, or a diaper bag next to one of these brass spittoons," Durbin said.
WLS-TV contributed to this report.
Copyright 2018 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved.