Matildas captain and Chelsea striker Kerr gave the news on Instagram with the words "Mewis-Kerr baby coming 2025!" plus photos of herself and pregnant partner Mewis, an American who plays for West Ham United.
Among support from well-wishers, the post also attracted some homophobic vitriol.
"It is very, very disappointing," Wiegman told a news conference on Tuesday. "I'm really happy for them, they look really happy and I hope it all goes well."
Bompastor said: "I just want to fully support Sam. This is just unacceptable, to have these kind of comments, especially in our world in 2024.
"That's just crazy for me to understand, how people can react like this.
"But what can I say? I just want to focus on the positives and give all my support to Sam and Kristie, tell them we are really proud. We are really happy for them."
Sitting alongside her at a press conference to preview Chelsea's Champions League match with Celtic on Wednesday, club captain and England international Millie Bright said: "We're just really happy for them both, just seeing the joy that it brings to both of them.
"I think that's what we're all put on Earth for, to bring joy to one another. We've not got the time of day for certain comments.
"Our focus is to spread happiness and to be there for one another, to support each other regardless of everyone's situation."
Chelsea said in an earlier statement to Reuters that they were aware of "unacceptable and hateful homophobic comments" on various social media platforms.
"There is no place in society for any form of discrimination and we will not accept any abuse directed towards our players, staff or supporters," a club spokesperson said.
"We are extremely proud to be a diverse, inclusive club that celebrates and welcomes people from all cultures, communities and identities."
West Ham shared what they called Kerr's "heartwarming" baby announcement on the team's website.
"Mewis has announced the wonderful news that she is expecting her first child," the club said.
"Everyone at West Ham United would like to congratulate Kristie and Sam on their fantastic news!"
Kerr is considered one of the world's top female strikers, scoring 199 career goals across the Women's Super League, Australia's W-League and the National Women's Soccer League, plus 69 goals for her country.
But she has been sidelined since suffering an anterior cruciate ligament injury in January.
The 31-year-old averaged nearly 30 goals in her previous three seasons for Chelsea. The 33-year-old Mewis has been capped more than 50 times for the United States.
The couple met in 2020 and became engaged two years later.
