She was the first Democrat to say publicly that Weiner should step down, though others joined in later Wednesday, as the New York representative admitted through a spokesman that he was both the subject and sender of an X-rated picture of a man's genitals circulating on the Internet.
Separately, several media outlets reported that Weiner's wife - Huma Abedin, a top aide to Secretary of State Hillary Clinton - is pregnant with the couple's first child.
The statement from Schwartz, who is in charge of candidate recruitment and member services for the Democratic Congressional Campaign Committee, was interpreted as a strong signal that the party leadership wants Weiner out of the House - and out of the way.
But Schwartz said she did not talk to colleagues about the issue before making her statement. The House is not in session this week and Schwartz was away last week mourning the death of her father.
"I had a very individual, personal reaction," Schwartz said. "Maybe it's because I was hearing about it as other Americans were hearing it, unfiltered by conversations with colleagues."
Weiner, in his eighth term representing a district in Brooklyn and Queens, has made no comment since saying at a news conference on Monday that he would not resign.
At the news conference, Weiner admitted to sending a photo of his bulging underpants to a woman on Twitter - after claiming for nearly a week that his account on the social-media service had been hacked. That photo was unearthed and first reported by Andrew Breitbart, a prominent conservative blogger.
At the news conference, Weiner also said he exchanged messages and photos of an explicit nature with about six women over the last three years.
The Weiner controversy has dominated the news and deflected attention from the debate over the nation's debt limit, as well as Democrats' efforts to batter Republicans for proposing to privatize Medicare.
