The 53-year-old presenter is said to have called Michelle Rounds - who she split from last November - after learning she planned to end her life and overdosed on pills.
According to TMZ, Rosie got someone to call emergency services while she stayed on the phone with her former partner, with sources telling the website Michelle "wouldn't be alive today" if she hadn't intervened.
Law enforcement services confirmed to the site that Michelle was rushed to a local hospital in New Jersey from a hotel at 11.15pm on Tuesday.
The insider said the trigger for the incident was Michelle losing custody of two-year-old daughter Dakota to Rosie.
Michelle previously insisted she should have care of the tot because her former partner left her in the care of nannies and never disciplined the little girl.
Speaking before the custody case, she said: "Right now she has 24/7 nannies over there at Rosie's house.
I don't want my child to have a nanny. I want her to be outside playing, I want to be with her. I want to go to all the parent conferences ... and that's just not what it's about over there.
"I'm at my daughter's every beck and call. I give her mild discipline instead of, like, carte blanche, do whatever you want, which is more or less how Rosie likes to do things."
Rosie filed for divorce against her second wife in Manhattan Supreme Court in February, just two weeks after quitting 'The View', saying she needed to spend more time with her kids and concentrate on her health.
The 'Flintstones' actress then initiated the uncontested proceeding against Michelle in Manhattan in February after nearly three years of marriage. They split last November and had been living apart for months.