JACKSONVILLE, Fla. -

Heather Palmer recalls the moment she realized her daughter Margaret was gone.

"As soon as I saw her foot, I knew something was wrong, the color of her foot was wrong.  We just both started screaming, because what else do you do in that moment?"

"I wanted to be in the ambulance but there just wasn't any room," recalled Mike Palmer.

Three-month-old Margaret Palmer stopped breathing in the middle of the night and died.

"She was perfectly healthy, yes perfectly. She had a well check that day," recalled the Palmer's.

Margaret had no symptoms of illness.

"We talked with the medical examiner, all the people who had put their hands on this baby. What could this be?  And there's no answer. Ultimately when there's no answer, then the answer is SIDS," said Heather.

Heather and Mike Palmer knew about Sudden Infant Death Syndrome.  Margaret was their fourth child and Heather is a Doula.

"I've been doing prenatal education for over 10 years. SIDS is something I have talked about, certainly something I've taught about," explained Heather.

They knew to put their daughter to sleep on her back to reduce the risk with no blankets or pillows to reduce the chances of suffocation.

"We did all those things," recalled Heather.

Channel 4 asked local pediatrician Dr. Bruce McIntosh how he can explain that.

"We know it's a tragedy.  We can reduce the risk of SIDS, but we can't eliminate it," said McIntosh, who's been a pediatrician in our area for more than 40 years.

We asked, "What are the leading theories on what could be what is causing SIDS? 

"The leading theory is that it has something to do with the control of breathing, something wrong with that part of the brain that controls breathing," McIntosh explained.

Studies also show that babies who are born early, premature, have a birth defect or whose mother smoked either during pregnancy or around her newborn are at a much greater risk of dying of SIDS.  And, nearly all babies who die are between 2 and 3 months old.       

But the greatest way to prevent SIDS, by 50 percent, is putting your baby to sleep on his or her back.  Sadly, like with Margaret, not even that is a guarantee.

"There are still cases that occur despite parents' best efforts. We don't know why," said McIntosh. "Hopefully time will tell hopefully science will help answer this but unfortunately we don't know."

For the Palmer's, not knowing what caused their daughter's death was gut wrenching at first, but their three daughters and the outpouring of support has made the not knowing less important.

"They mowed the yard, cleaned the house, normal things to take care of. They came and did without mentioning it," explained Mike. "The only real comfort we have is the love we have for each other.  Our family and the love other people are showing us and that's what I need to know about."

"I've talked to people about reducing the risk of SIDS and I've framed that argument with the idea that you can prevent it, but the fact of the matter is our culture is obsessed with preventing everything and some times, some things are just unpreventable, sometimes things are just going to happen," said Heather.