Boston Mayor Michelle Wu is pregnant.

The mayor announced Monday that she and her husband, Conor Pewarski, are expecting their third child in January.

“Conor, Blaise, Cass and I can’t wait to welcome another little one to our family and to Boston,” Wu, 39, said in an email to supporters. “It hasn’t been an easy journey, but I’m due in January and couldn’t be more grateful.”

Wu did not mention whether her pregnancy would impact her current term and her plans to run for reelection. The Herald has learned that the mayor plans to run for a second term and will make a formal announcement saying so.

She did, however, point to her ability to juggle motherhood and public service in her email to supporters.

She became the first city councilor to give birth while serving in office, when she had her first child, Blaise, during her first term in December 2014. Wu gave birth to her second child, Cass, in July 2017 when she was president of the City Council.

The mayor also balanced a caretaker role prior to being elected to office, when she took over care for her mentally ill mother and two younger sisters at age 22.

She has cited the caretaker responsibility as one of the factors that drove her to pursue a career in politics. As a city councilor, for example, she filed legislation to establish the City of Boston’s first-ever paid parental leave policy to ensure city workers get six weeks of paid leave after the birth or adoption of a child.

Wu later helped to expand the policy to 12 weeks and include coverage for fathers, adoption and pregnancy loss.

As mayor, Wu has helped to settle collective bargaining contracts for working families, and has consistently shared her own experiences on public transportation, including when getting both kids to City Hall childcare and on the MBTA.

“I’ve been a mom and caregiver as long as I’ve been in public service,” Wu wrote. “It’s that daily juggle — and the struggle and dreams of families across our neighborhoods — that keep me grounded in the work and moving with urgency.

“I approach each day as a mom determined to create the best possible future for all of Boston’s families,” she said. “And we have so much more work to do.”