The senator, who will turn 50 years in March, already has a daughter, who was born in November 2014. Her second child, also a girl, is due in April.
Duckworth lost both her legs during the Iraq War, when the Black Hawk helicopter she was piloting got hit by a rocket-propelled grenade in 2004.
She was elected to the Senate after representing Illinois' 8th Congressional District in the U.S. House of Representatives for two terms last year. She is a former US Army Lieutenant Colonel as well.
She also served as the assistant secretary of the Department of Veterans Affairs.
In September last year, Duckworth wrote an editorial for Cosmopolitan, advocating for more lactation rooms in all US airports. (ANI)