Stephanie Nielson gave birth to her fifth child, Charlotte, last month. (Credit: Stephanie Nielson)

The day your first  book hits stores is a big one for any first-time author, but on April 3 - the publication date of her now best-seller, " Heaven Is Here" - Stephanie Nielson was preoccupied with something else: the birth of her fifth child, Charlotte.

Charlotte was a child whom Nielson, a popular mom blogger, and her husband, Christian, worried they might never have. In August  2008, the couple was in a horrific plane crash. Nielson experienced burns on more than 80 percent of her body and was in a coma for four months. When she woke up, her scars had changed her appearance so dramatically that her children couldn't even look at her.

Watch "20/20's" interview with Stephanie Nielson here.

In "Heaven Is Here," Nielson describes her long physical and emotional journey toward recovery, including rebuilding her relationship with her four children.

She said she began thinking of having a fifth child about two years after the accident.

"I thought, 'Enough surgeries, I'm done doing surgeries, now I'd like to continue my family,"" Nielson, 30, told me.

But pregnancy after enduring injuries like Nielson's was no simple endeavor. Nielson had to wean herself off  pain medications and was checked regularly to make sure her skin was stretching properly to accommodate her growing belly.

"The upper part of my belly was burned but the lower part where the baby fits comfortably for most women - that was not burned," she explained. "I had a good portion of good skin that was not burned. That's the reason I was able to do this. Otherwise I don't think it would have worked out."

Challenging as her pregnancy was, being a mother to Charlotte has been "motherhood at its best," she said.

"It's been sleepy nights, busy days," she said. "It's what I wanted and it's a miracle."

With the addition of Charlotte, the girls now outnumber the boys in the Nielson family. "We won!" Stephanie Nielson joked.

MORE PHOTOS: Stephanie Nielson and her family