New York Mom Leaves Heartwarming Messages for Daughter Before Dying of Cancer

— -- Liz Joice of New York City lost her battle with cancer six weeks after giving birth, but she'll still have a presence in her daughter's life thanks to heartwarming video messages she left behind.

New Jersey director Christopher Henze worked with Joice to direct, film and animate the videos, and they are featured in his recent documentary, “40 Weeks,” which follows 12 women throughout their pregnancies. Henze added childlike animations to the video clips that the now-1-year-old Lily Joice views on an iPad.

"I took 70 hours of footage of Liz and her husband, Max, and we created a piece for Lily so she could continue to see her mother and hear her mother’s voice," Henze told ABC News. "It’s a correlation of Liz and Max together. She [Lily] loves it, by the way."

One video clip begins with Lily's parents revealing her gender to the camera.

"So we found out ..." Max Joice says.

"It's a girl!," Liz Joice chimes in, with a laugh.

Other videos Lily can watch include footage of Joice interacting with characters from children's television shows, such as when Joice is shown spilling tomato sauce and a song from the show "Yo Gabba Gabba" chimes in an exhortation to "clean it up," Henze said.

Henze, who became good friends with the couple while filming Joice from July 2013 until February 2014, said that the New Jersey native first beat undifferentiated sarcoma -- which begins in the body's connective tissues -- in 2011 and was in remission until her diagnosis returned during week 12 of her pregnancy.

Joice underwent surgery to remove the tumor in her spine and held off on "aggressive chemotherapy" until Lily's birth by c-section on Jan. 23, 2014, Henze said. Joice died on March 9, 2014 at age 36.

Even toward the end of her life and in a weakened state, Henze said Joice remained positive throughout filming.

"She expressed such gratitude because she said her and her husband would’ve never documented anything," he said. "Even though she was going through such challenges, her smile was so broad. She was enthusiastic about us doing this.

"Max, at her memorial, said something that fits," Henze said. "'Liz made you feel like you could be the best of yourself and then had the compassion to help you become that.'"

"That’s one of the things he’ll miss the most," he added. "For me, she was an inspiration by saying things like, 'You can’t control what happens, but you can control how you deal with it.' She also said, 'Anger is a useless emotion. It only brings you down. I don’t have time for anger.'”

Max Joice, reached through Henze, declined to comment for this article.

Dr. Jennifer Ashton, ABC News medical contributor and a practicing OBGYN, said Joice's story is tragic, but cancer treatments for pregnant women have made huge strides in recent years, and every case is different.

"Things are evolving a lot in these fields of high-risk obstetrics and oncology," Ashton said. "The key is being treated at a high-volume academic medical center that sees lots of patients like this, and where care for premies is top-notch. Readers should keep in mind that since women are often seeing doctors more often while pregnant, finding cancer during pregnancy does occur, and is often one of the most emotionally and physically stressful situations we see in medicine."

"40 Weeks" premiered in theaters Dec. 1, 2014 and on DVD and download via Amazon and iTunes on April 1, 2015.

ABC News' Sydney Lupkin contributed to this report.