Speaking at a gala benefit for the Children's Hospital Los Angeles, the singer and actress recounted how "nervous" she and husband Marc Anthony had been as they waited for then three-week-old Emme's test results.
"I just remember my heart sinking to my feet. I looked at [Marc] and I said, 'You know if anything happens, I'm not going to be okay, you know that right?'" she explained.
She went on to say that Emme had undergone a variety of medical tests, including an MRI, before being discharged.
"Luckily in the end she turned out fine... [but] I started to wonder what if I couldn't afford a doctor, or receive the medicines, the procedures?"
Lopez, who gave birth to twins Emme and Max in February 2008, added that the experience had led her to join the Children's Hospital to help form a foundation that provides medical services to less fortunate children.