The 50-year-old soap expert is mother to three-year-old daughter Betsey, who she welcomed after seven rounds of IVF and two miscarriages.
Marshall told OK! Magazine: "There was one day, just after I'd had a miscarriage, and there was an item on the show about the most beautiful babies in Britain.
"They were so lovely and Amanda told me to go and get counselling, which I did. I got the loveliest message from her when I got pregnant."
Holden, 50, suffered the heartbreak of a stillbirth at seven months in 2011, losing her son Theo.
And Marshall also revealed that fellow This Morning presenter Alison Hammond, 46, offered to be a surrogate mother for her.
Marshall said: "She has the most beautiful soul, to offer to do that for me. The one thing I miss in COVID times is my Alison hugs!"
The TV presenter has previously revealed that six months into her pregnancy with Betsey she woke up in the night bleeding and was terrified she would lose her.
She previously told The Sun: "Before she was born I was convinced something was going to go wrong.
"Until Betsey was actually put in my arms and I heard her let out the most almighty yell, I always felt like someone was going to say it's all going to be taken away from me.
"I'd never allowed myself to go and buy something for the baby before I'd given birth.
"I wouldn't even let myself look at the baby clothes in a shop. I was terrified to jinx it."
Watch: This Morning shows CCTV footage of Alison Hammond falling in her garden