The congresswoman is locked in nonpartisan debate with her husband over a name for the baby boy, who is due May 29.
"We're getting lots of suggestions," she said, while declining to list the favorites.
This blessed event is a rarity. McMorris Rodgers, R-Wash., is just the fifth woman to give birth while serving in Congress, according to research by her aides. All have been members of the House.
Yvonne Brathwaite Burke, D-Calif., was believed to be the first when she gave birth to a daughter in 1973. After her, Enid Greene, R-Utah, had a daughter in 1995.
The last member of Congress to give birth while in office was Blanche Lincoln, D-Ark., whose twin sons were born in June 1996. Susan Molinari, R-N.Y., gave birth to a daughter six weeks before Lincoln.
"Being pregnant and being in Congress is like being pregnant and working any other job, it's just a more public pregnancy," Molinari, now head of a lobbying firm, said in an e-mail to The Associated Press.
For Lincoln, being pregnant was overwhelming and she did not seek re-election to the House in 1996.
"When my husband, Steve, and I discovered that we were having twins, we started thinking about how difficult it would be to carry two sets of everything back and forth from Arkansas to Washington, D.C.," she said.
Two years later, Lincoln returned to politics and won the Senate seat she now holds.
McMorris Rodgers, 37, learned she was pregnant while campaigning last summer for a second term. She chose not to reveal the pregnancy until after the election, which she won easily.
She was first elected to Congress as Cathy McMorris in 2004. Then she met Brian Rodgers, 50, a retired Navy officer and son of a former Spokane mayor, in 2005. They married in San Diego last August.
"This is the last thing I thought would happen during my first chaotic year in Congress," she said when she announced her engagement last year.
The pregnancy, McMorris Rodgers said, has been relatively easy. There was a little morning sickness, but no cravings for specific foods.
"I'm just hungry a lot," she said.
McMorris Rodgers, a conservative Republican, does not expect motherhood to change her political views, spokeswoman Jill Strait said.
Molinari also said having a child did not change her views.
"I was always interested in issues concerning child care, families and medical issues," she wrote. "However, raising children has made me much more understanding of the politics process overall."
Molinari said she used day care after her daughter was born so she could continue to work, and also brought her to the office some days. After a trip to her Eastern Washington district in mid-April, McMorris Rodgers said she will stick close to her Capitol Hill home for the final month of the pregnancy. "My goal is to have a natural birth," she said. She has not decided how much time she will take off. "I'm not going to be in the office for probably three weeks, and just try to be available for votes when possible," she said. Lawmakers usually have enough time to get to the House when important votes are called, she said. She will also benefit from Congress' Memorial Day break, she said. But June and July will bring action on budget bills, which typically mean lots of long days, she said. She also may bring the baby to work. "One of the positives about this job is you do have a flexible schedule," McMorris Rodgers said. "I hope that allows me to spend quality time with the baby." "Also, I have a spouse," she noted. "He's excited about being a caregiver." A baby can create political problems. A few years ago, former Massachusetts Lt. Gov. Jane M. Swift got into hot water for using her staff to baby-sit her infant daughter. Plenty of women in Congress had children before they were elected, and McMorris has been talking with them. Asked about additional children, she said, "We'll see how it goes."