Triplets Leo, Eli and Oscar Radido were born nine weeks' early at the Princess Anne Hospital in Southampton.
While Eli and Leo were able to go home five weeks later, little Oscar who, at birth, weighed just 1lb 9.75oz (730g) - less than a loaf of bread - spent an extra month in the neonatal unit.
Their mum, Victoria, says it was a scary and isolating time.
A new video app being used by staff at the hospital let her watch her babies and see how they were doing.
Victoria said: "The first time I met them they were all in incubators, obviously covered in tubes and wires. They were so tiny and they looked so fragile.
"It's hard. Everyone else gets to take their babies home and ours have to stay here. You have to leave them every day and that's really difficult."
About 60,000 babies - one in every 13 - are born prematurely each year in the UK.
Southampton's neonatal unit is one of 60 in the UK using the trusted NHS app to help connect new parents with their babies around the clock.
Staff use it to take photos and videos that can be forwarded to the mum and dad.
Victoria and her partner Derrick were able to log on to the app at home and see updates on their babies, even in the middle of the night.
Victoria said: "You get this lovely picture and it usually has a message saying 'Hi mummy, Hi daddy. Having a lovely evening'.
"You have to leave your babies and you feel so guilty leaving them. To know that they are in such safe hands, and with people who care enough to take a picture and just send it to you to make you feel good, is amazing."
Fiona Lawson, a matron at the hospital, said it was a wrench for parents to be separated from their baby or in Victoria's case, babies.
"To be able to soften that blow by sending them videos, sending them photos, little messages, is really lovely for us to do."
Hospital charities fund the secure vCreate app so it is free for the parents to use.
Over the last two years more than 5,000 families have benefited.
It is hoped that the app will be available in nearly half of the UK's neonatal units by early next year.