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The murder of two young children, allegedly at the hands of their beloved nanny, has sent a chill through working mothers already conflicted over the often agonizing decision to leave their children in the care of others while they work to put food on the family table.

Marina Krim, a pediatrician who stayed at home with her three children until a year ago, came home to every mother's worst nightmare Thursday, finding  Leo, 2, and Lucia, 6, stabbed to death in the bathtub and once-trusted nanny Yoselyn Ortega, 50, bleeding from what police believe were self-inflicted wounds. Ortega had been referred to the Krims by another family, authorities said.

Police said Ortega, a native of the Dominican Republic who was in the U.S. legally, has not yet been interviewed or charged. She is in critical but stable condition at New York Presbyterian Hospital.

A day after the murders, mothers in New York City and beyond - as well as nannies - reacted to the horror with disbelief and sadness.

"This could have happened to anybody," said Leslie Venokur, a working mom who runs the website bigcitymoms.com. "We put so much trust in our caregivers. Yes, I’m sure you have some moms who maybe rethink their working hours but I also think it’s a conversation that parents need to have with their caregivers about the situation that just occurred.

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    "I didn’t have to even bring it up with my nanny this morning," said Venokur, whose site is a network for more than 100,000 working moms. "She just hugged me and said 'I love your children as if they’re my own.'"

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    Clifford Greenhouse, president of New York household staffing firm Pavilion Agency, said dozens of nannies have called his agency distraught over the deaths.

    "They’re devastated, they’re terribly sad," Greenhouse said. "They’re worried this would be a negative reflection on them. And whether you’re a nanny, a schoolteacher or any other kind of caregiver, it just affects you. It affects all of us."

    Greenhouse said his agency like other reputable firms do criminal background checks. But he said the interview process and meticulous checking of references is the best way to ensure a nanny is right for your kids. Relying merely on instincts and even a referral like the Krims appear to have gotten is not enough, he said.

    “The nannies we work with must display a record showing they have worked for families for five, 10 years, with long-term references and moms who I can get on the phone and ask the pointed questions about their judgment,” Greenhouse said.

    Greenhouse said working moms who read the tragic news “are petrified, as they should be.”

    “They’re going to take every measure conceivable to ensure that whoever they engage to raise their children are screened and vetted as much as humanly possible,” he said. “That said, my experience is the vast majority of parents have been going forward using this approach long before this awful event.”

    The deaths, while tragic and disturbing, did not seem to have an immediate effect on the decision by most working mothers to go off to the job.

    "As a working mom who leaves her school-age children with a nanny during post-school hours, I don't believe that one person's horrible and intensely sad experience should be assumed to be a rampant issue or parental concern in the nanny world," Hope Goldberg, a mother of two from Maplewood, N.J., said.

    "It's no different than any other random act of violence that no-one can explain," Goldberg said. "As a mom, you take a giant leap of faith -- even after all the criminal checks and references are secured -- that you are leaving your children with a caring adult and out of harm's way...After hearing this story, we will hug our children this evening when we return home from work even harder and pay our nannies and babysitters for their week's pay and thank them for keeping them safe."

    FoxNews.com's Brooke Lefferts contributed to this report.