Sen. Tammy Duckworth pregnant with 2nd child

Sen. Tammy Duckworth, D-Ill., is expecting her second child, and when she gives birth this spring, she will be the first senator to do so while in office.

Duckworth's first child, Abigail, was born in November 2014, when she was serving in the U.S. House of Representatives.

"Bryan and I are thrilled that our family is getting a little bit bigger, and Abigail is ecstatic to welcome her baby sister home this spring," Duckworth, 49, said in a statement Tuesday. "We are all so grateful for the love and support of our friends and family, and I want to thank the wonderful staff at both Northwestern Medicine and GW for everything they've done to help us in our decades-long journey to complete our family."

A combat veteran of the Iraq war who lost both legs in 2004 when the Black Hawk helicopter she was piloting was struck by a rocket-propelled grenade, Duckworth has served in the Senate since January of last year.

Duckworth took to Twitter to share the news, writing, "Wanted to share some exciting personal news...," along with an image of four ducks, captioned, "Duck, duck, duck...duckling!"

A couple hours later, she tweeted again, writing, "Thank you for the outpouring of congratulations and support. I'm hardly alone or unique as a working parent, and my daughter Abigail has only made me more committed to doing my job and standing up for hardworking families everywhere."

Sen. Richard Durbin, Duckworth's Illinois colleague, congratulated her on the news.

The news also drew congratulations from a handful of other U.S. senators.

According to Duckworth's office, she will be "only of only "10 women since our nation's founding who have given birth while serving in Congress," giving her a unique perspective on certain issues.

"Parenthood isn't just a women's issue, it's an economic issue and an issue that affects all parents-men and women alike," Duckworth said in the statement released by her office. "As tough as juggling the demands of motherhood and being a Senator can be, I'm hardly alone or unique as a working parent, and Abigail has only made me more committed to doing my job and standing up for hardworking families everywhere."