Karisa Bugal, 34, was happily awaiting the birth of her and her husband's second child when she went into labour on 3rd November.

READ: HOW TO DEAL WITH GRIEF AND SEPARATION

But, when doctors at the hospital checked her over, they discovered that she had a rare and unpreventable condition called amniotic fluid embolism.

Dr. Kelly Gerow told KUSA-TV said: "The amniotic fluids surrounding the baby or part of the baby's skin or hair gets into the mother's bloodstream and that causes catastrophic shutdown of all the organs.

"We don't know how to prevent it. We don't know how to keep it from happening at all."

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Experts say around 1 to 12 mothers in every 100,000 deliveries have amniotic fluid embolism - and many of the mothers who develop the condition do not survive.

Because of the condition, Karisa's unborn baby's heart rate began to dip, and the mother was faced with a horrible choice: Have a C-section and save his life, or delay and save her own.

"Her other option would have been to stay awake for her surgery, but by the time we would have put in a spinal tap or something it's possible Declan would not have made it," Dr. Gerow continued to tell the NBC-affiliated TV channel.

Karisa did not hesitate; she asked doctors to perform a caesarian in a bid to save her baby - knowing full well that the procedure would most likely kill her.

At around 7:30 a.m. on 4th November, Declan Jay Bugal, a healthy, 7-pound, 4-ounce baby boy, was born.

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The staff told his mother that her miracle baby had made it, then wheeled her to the ICU, where she passed away shortly thereafter.

Her last words were, "How big is he?"

Wes Bugal, Karisa's husband, said words can not describe the challenge of moving forward with a toddler, a newborn and no wife.

"How do I explain to him that his mom is gone giving birth to him? I think about that all the time," Wes Bugal said. "How do I explain when he asks where's mommy?"

A GoFundMe page has been set up for the Bugals. You can find that here.