WASHINGTON — Illinois Sen. Tammy Duckworth is pregnant with her second child. She will be the first U.S. senator to give birth while in office. The 49-year-old Democrat, a veteran who lost her legs in the Iraq War, announced her pregnancy in a news release Tuesday. “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.