The 33-year-old actress made the revelation in an interview for Women's Health, reported Ace Showbiz.
"I had tumors on both ovaries, and the cancer had spread into my lymph nodes and surrounding tissues," Smulders said.
For the next couple of years, she underwent many surgeries to remove the cancerous tissue in her body, which then left her with one third of an ovary. Being told by doctors who treated her that she would never be able to get pregnant naturally, Smulders in fact has two children with her actor husband Taran Killam.