When mum to be Lucy Lintott was in hospital for the birth of her first child, her partner likened the anxious wait for the battle ahead to the kind of nervous tension felt by a Tommy in the First World War.

Trying to lighten the moment in the labour suite, he mused: “It’s like the part where they’re going over the top in the trenches.”

Lucy, her broad smile ever present despite the devastating diagnosis of Motor Neurone Disease when she was just 19, replied softly: “Or when you go over the top… and you don’t come back.”

The intensely private and heart wrenching moment shared by a couple who already know their time together is drastically limited and with childbirth raising the stakes even higher, is revealed in a new film that follows their battle to become parents.

Captured from the beginning of their journey into parenthood, it uncovers the immense courage of both as they defy the cruel condition to welcome into the world first their baby son, LJ, and then, incredibly, their baby daughter.

Both pregnancies defied the odds – the impact of MND on Lucy’s body meant it was not known exactly how she might cope with the challenges of carrying and delivering not one, but two healthy babies.

While any pregnancy brings a degree of worry and fear, the impact MND has already had on Lucy’s health meant her passage into motherhood brought a terrifying risk that either she or her baby might not make it and, in the worst possible scenario, neither would survive.

The possibility of such a dreadful outcome lingers in the background as the young couple, from Elgin, share the joy of seeing their baby’s son’s image during a scan and, months later, anxiously wait for Lucy’s labour to kick in.

Having a second baby was particularly fraught: Lucy, who is now in a wheelchair as a result of her illness, is believed to be the only woman with MND to have given birth twice while in the grip of the condition.

Her case is now being used in medical studies, bringing hope to other young women facing the nightmare of discovering they have the progressively wasting disease.

Lucy was given just 18 months to live after being diagnosed with MND – the same condition as rugby legend Doddie Weir – when she was still a teenager.

Until then carefree with a love of sports and outdoors, she recalls being diagnosed by a neurologist but not understanding what MND was, or that it would eventually leave her paralysed.

“When he told me it was incurable I started crying. I didn’t want to fall over all the time, I didn’t think it could get worse,” she says.

“But the progression has been extremely slow and it has given me time to figure out what I wanted.”

In a remarkable display of resilience, Lucy resolved to live independently, moving out of her parents’ home and into her own flat to live with the support of carers.

As well as working to grow awareness of the debilitating condition, she has raised around £200,000 to help find a cure and received a string of awards.

But, the programme shows, at the back of her mind, she dreamed of becoming a mother despite warnings from medics of the risks.

Although she had met fiancé Tommy at school, it was only when he shaved his head to raise money for MND, that their romance took off.

The documentary shows their deep commitment to spend as much time together as possible making precious memories and, perhaps in a lesson to us all, disregarding material things in favour of devoting time to those they love.

The couple and their families talk openly of their fears that pregnancy could put too much stress on Lucy’s body, and the decision to have just Tommy and her mother at the birth.

“With any woman who is pregnant, they are risking their lives,” Lucy tells the programme before her son, LJ, was born. “With me having MND the risk is higher, because they don’t know how my muscles will react. “Obviously that’s something that me and Tommy have talked about and did discuss before deciding to try for a baby.

“The fear that he could lose me, and I could lose him or leave him is too high a risk to let anyone in the room other than my mum and him, because that could be last time he sees me, and it could be the only time I see my son,” she adds.

The couple are later shown embracing their new-born son, LJ, marvelling over his mop of blond hair and pondering his future.

The birth meant she was one of only five women in the world known to have delivered a child while battled MND.

“I couldn’t ask for more,” Tommy tells the programme, adding, poignantly: “We are going home as a family, and I’m not going home alone.”

Incredibly, within just a few months, the couple revealed they were expecting a second child. Their daughter, who they call AR, arrived in December last year.

The programme also shows how Lucy has captured her voice on a series of recordings so as her speech deteriorates, she can carry on cracking jokes.

And it highlights how Tommy, 26, a plumber and heating engineer, has dealt with the demands of fatherhood and caring for his fiancée while juggling work and navigating his way around Lucy’s teams of carers.

Most touching are intimate moments that show the couple revelling in each other’s company, determined to make the most of their time together regardless of what lies ahead.

Tommy says: “Everyone is always chasing money - there’s more to life than money.

“No single amount of money, large, small, millions, billions could give me a better life with Lucy. Just love the person you’re with and make sure every moment counts.

He adds: “She has so much courage to get up every day and live the way she does. She has acceptance of her condition. She is amazing.”

The couple are now preparing to marry, after their original wedding date was postponed due to Covid restrictions.

Although the spectre of MND is never far away, it does not dampen the couple’s spirits.

“I have got the family I always wanted which shows that life is very much for living,” concludes Lucy.

“I’m so grateful. I take every day as it comes. I don’t know how long I have left, because of that we seize every moment and live life to the fullest.”

Being Mum with MND is on BBC Scotland on Tuesday, May 3, at 10pm