Media playback is unsupported on your device Media caption Liver transplant beneficiary: 'I have a baby boy thanks to you'

Ellie Lacey was just hours from death, desperately needing an urgent liver transplant. Two years on, the 32-year-old from Cardiff is a new mum and has written to her organ donor's family to express her joy at life while acknowledging their terrible loss.

It was seven long months after finding out I was pregnant, that I finally mustered the courage to sit down and write.

I had been putting it off, not because I didn't want to write, but because I didn't know how.

I was so happy about my news, I knew how blessed and fortunate I'd been, but as I began to scratch out the words, an enormous wave of emotion and sadness hit me.

Image copyright Ellie Lacey Image caption Baby Otto was born on 21 December weighing in at weighing 7lb 8oz

Regardless, I began…

To my dear donor's family…

It has been nearly two years since my liver transplant and I have something to tell you…

But then I stopped, my pen down, my head in my hands.

For as much as I wanted to let them know that their loved one's liver had not only allowed me to live, but had allowed me to bring new life into the world, I also knew hearing from me must be so bittersweet.

The brutal truth of the situation was that I was only alive because their loved one had died.

Yet how could I not keep thanking them, and letting them know how much they are in my hearts?

Image caption Ellie Lacey was hours from death in desperate need of a transplant

It wasn't the first letter I had written to them.

Just after my operation, when I was on a massive high at having cheated death, I wrote, gushing with excitement.

I had hoped my joy might be a silver lining to their sadness.

I never got a reply and I'm not surprised. I was so insensitive and blind to their loss.

I wrote again last Christmas, a very short letter to say I never stopped thinking about them - and now this.

Of course, like every young person, I never expected to be in the position where I would need a donor organ in my body.

I had been very fit and healthy, newly married and looking forward to life.

I worked in marketing and spent weekends competing around the UK in wild, windy fell races.

Then, out of nowhere and for no discernible reason, in January 2017, my liver failed and I needed a transplant.

I began to get very ill, turning yellow and ending up in intensive care.

Over a matter of days, my body had collapsed.

Image copyright Ellie Lacey Image caption Ellie in hospital, 10 days before her transplant

Eventually, I was in and out of consciousness, connected to machines and wires with a team of doctors rushing around me.

My family members weren't compatible donors, so I was put at the very top of the worldwide donor list for my blood type O.

Doctors told my family that a liver would likely be found for me that night.

In the end, it took three days, coming in at the point I had just hours to live.

During that time, I had said goodbye to the world.

Yes, I wanted to live - to have more time with my loved ones and one day start a family, but I was also at peace.

I knew I had loved and been loved, and I knew - after setting up a marathon in Uganda - that I had also made a difference in the world.

Image copyright Ellie Lacey Image caption Ellie organises the Running The Rift marathon in Uganda to raise money for charity

Then, amazingly, an organ was found.

It came in late at night to a hospital in the Midlands.

It was transported down, then I was operated on the following day.

When I woke up, although I was incredibly weak, to the point I couldn't walk, I was also euphoric.

How many other terminally ill people get a chance to live again?

Of course, the euphoria was eventually replaced by a huge low as I came to terms with everything.

But as I struggled to get back to normal, there was barely a moment I didn't think about my donor.

I was told she was a woman in her sixties who had died from a stroke.

And I was told I was allowed to write to her family, via the hospital, if I didn't reveal my full name.

Image copyright Ellie Lacey Image caption Ellie keeping fit during her pregnancy

I can't explain how much I wanted to write to thank them.

It was down to them that I was able to live.

I also wanted to tell them about the pregnancy and how much it meant to me.

You see, trying for a baby had not been an easy decision to make.

Because of my transplant, I was high risk.

Image copyright Ellie Lacey Image caption Ellie competing in the British Transplant Games in 2017

There was a 10% chance my body might reject the liver.

There was also a bigger risk of pre-eclampsia - a condition caused by high blood pressure - and having a premature baby.

First and foremost, I did not want to be a burden on the NHS again - or to need a new organ.

But I had also vowed to myself, after coming so close to death, that I would live life to the full, not just for me but for my donor too - so that's what I and my husband Paul, who's 33, decided to do.

Image copyright Ellie Lacey Image caption Following her transplant, Ellie wanted to live life to the full and experience motherhood

Thankfully, all went smoothly.

And my beautiful boy, Otto Lacey, was born on 21 December 2018, weighing 7lb 8oz (3,5kg) and becoming our best Christmas present ever.

He really is perfect in every way.

Eventually, I did finish and send my letter to the family, explaining that while nothing will bring their loved one back to them, she has left a lifelong legacy within our family and that she's our hero.

Whether they reply or not, I will have to wait and see.

Image copyright Ellie Lacey Image caption Baby Otto James Lacey weighed 7lb 8oz

Either way, my boy will now grow up knowing about this lady who saved my life.

He will know there are good people in the world who think of others.

And he will know what it means to be kind and selfless.