The birth of a baby should be a wonderful occasion, but for Emma Jackson it was a crushing reminder of the husband she had just lost.  Here Emma, 33, from Wychwood, Oxfordshire, explains how she learned to smile again...

The sun was shining, I was five months pregnant with my first baby and as I walked on my way to work I couldn't help thinking how lucky I was. 

Only a couple of days ago my husband Andrew and I had visited the antenatal and maternity ward where we were planning to have our baby.  And we were happily planning our baby's nursery. 

That hot May morning I'd got up early.  As Andrew dozed in bed, I leant over and gently kissed his cheek. 

"See you later," I murmured. 

My last memory as I left our flat that morning was Andrew in his pyjamas padding into the bathroom - it was the last time I saw him alive. 

At 10am that morning, I was in a business meeting when the phone rang.  Someone was calling me from Charing Cross Hospital, London, a few minutes from my office in the City. 

"There's a problem with your husband," said the voice on the phone. 

"You need to get here now." 

I felt cold and panicky, wondering what could possibly be wrong.  Andrew had recently made a resolution to get fit and had been to the gym that morning.  I wondered if he'd been run over while crossing the road. 

The next few hours passed in a blur.  Inside me, our unborn baby kicked as a taxi drove me to hospital.  I tried to keep calm, telling myself Andrew was fine. 

But, inside I think I already knew he wasn't.  If he was OK, he would have called me himself. 

When I got to the hospital entrance, a member of staff was waiting for me.  My heart was almost bursting out of my chest as the nurse ushered me through to a side room. 

Then a doctor came in and her serious face said it all. 

"You've come to tell me my husband has died," I said. 

"Yes, I have," she replied. 

Someone took my hand and it felt like my world had stopped spinning.  I remember clutching my stomach, willing myself not to break down. 

I later discovered Andrew had gone to the gym and while he was on the treadmill, he'd collapsed.  Paramedics had tried to revive him but it was hopeless. 

At the age of just 30, my good-looking, funny husband - the man I'd met at university 10 years before and thought of as my soul mate - had just suddenly died.  I had no time to say goodbye or tell him how much I loved him. 

The loss felt overwhelming but, perhaps because I was pregnant, I felt strangely calm and detached.  Relatives offered me a place to stay but that evening all I wanted to do was to go home.  So, accompanied by my mum Diana, I went back to our London flat.  As we reached the front door, a single flower and a card from our neighbour was on the doorstep.  It was so surreal, I could barely take it in,  but seeing Andrew's green jacket hanging in the hall as I went in was strangely comforting. 

Over the following months, for the sake of our baby, I had to keep going.  Antenatal classes which we'd looked forward to together, were an ordeal even though my mum came with me. 

I tried to focus on my future.  I cleared a space in the flat for the cot.  And a few weeks before the birth I bought a dog, who I named Moffatt.  Looking back, I made myself too busy to grieve. 

A week after my due date, doctors decided to induce me.  As I walked into the hospital, I steeled myself - I was dreading doing this alone. 

Then halfway through the labour, when doctors said I needed an emergency caesarean, I suddenly felt calm.  It was almost as if Andrew was there, close to me, and I knew I could go on. 

When our son Thomas was laid in my arms, my heart lurched with love - and pain.  I should have been so happy yet, as my son's tiny hands curled round my fingers, the pent-up tears began rolling fast down my cheeks. 

Now Thomas was safely here, I could finally let go and cry properly for Andrew.  I sobbed as I realised that Thomas would never sit on his dad's shoulders or kick a football with him.  Worst was the thought that Andrew would never hold his beautiful son.  When I got home, the grief really kicked in.  I would weep until I was physically sick.  I had looked forward to these early months with my baby - but I'd never envisaged being a widow and lone mum. 

Despite so much help from friends and relatives, the reality of broken nights and constant feeds came as a crushing blow.  Exhausted and shattered with grief, some days I found myself simply going through the motions. 

Then I had another terrible shock.  Frustratingly, the post mortem didn't find anything wrong with Andrew. 

Why his heart gave out was a mystery as he was completely healthy.  At the inquest five months later, the verdict was Sudden Death Syndrome - in other words natural causes. 

I looked it up on the internet and came across a charity called Cardiac Risk in the Young (CRY).  I read that this type of sudden death affects up to 12 young, healthy people a week. 

Then fear struck as I discovered that Andrew's condition could be hereditary. 

Thomas, and Andrew's twin brother and younger sister would need to be tested with a drug to find out how their hearts reacted under stress.  Fortunately, when the test results came back, all of them were in the clear.  But Thomas will need life-long monitoring and it will always be a worry as it could occur in his children. 

As Thomas grew older, his smiles made me laugh, just like his dad's had done.  When the bad days hit, Thomas shook me out of it.  I've taken great comfort from his mannerisms, the way he plays with his fingers, the position he sleeps in, which are all undeniably Andrew's. 

Two and a half years after Andrew's death I moved from London to a cottage in the Oxfordshire countryside.  I left my job as an educational consultant and went to work part-time locally. 

Thomas is three years old now and my best friend as well as my son.  I talk to him about his daddy all the time and Thomas tells people he does have a daddy, but that he's in heaven. 

I still wear my wedding ring and sleep on my side of our double bed.  I can't imagine being with someone else because I'm still in love with my husband - the father of the child he never got to meet.