The 40-year-old actress has undergone surgery for endometriosis - in which tissue from the uterus grows outside of it - and is feeling "sore" after having the operation, but took the time to warn other women to see a doctor if they have "really painful" periods because they could have a similar problem.
She said in a video filmed by her husband Chris Fischer shared to Instagram on Saturday (18 September): "So, it's the morning after my surgery for endometriosis and my uterus is out.
"The doctor found 30 spots of endometriosis that he removed. He removed my appendix because the endometriosis had attacked it.
"There was a lot, a lot of blood in my uterus and I'm, you know, sore and I have some, like, gas pains."
She captioned the post: If you have really painful periods, you may have #endometriosis.(sic)"
The 'I Feel Pretty' star - who had also been diagnosed with adenomyosis, another condition relating to tissue in the uterus - previously admitted having endometriosis caused problems when she delivered her son Gene, now two.
She previously said: "Even through the birthing centre has an operating room and doctors at the ready ... my instincts were just like, no. I want to go back to Manhattan. I was throwing up through the whole first hour of my C-section. It's supposed to take about an hour and a half or something but mine took over three hours because of my endometriosis."
And after undergoing IVF treatment to conceive a second child, Amy admitted in August 2020 that she and Chris had decided against expanding their family because the process had been so "tough" on her.
She said: "We did IVF, and IVF was really tough on me. I don't think I could ever do IVF again.
"I decided that I can't be pregnant ever again. We thought about a surrogate, but I think we're going to hold off for right now."