The 33-year-old Saturdays star has said that post-birth exhaustion coupled with frustration at having difficulty breastfeeding caused her to burst into tears.
"I hadn't really slept in the hospital, so I was exhausted and the third day is when the baby blues tend to kick in," the mum-of-two told Hello! Magazine.
"It was also the day my milk came in, but I couldn't get Tadhg to latch on. I had a bit of a meltdown, sobbing, 'It's only been three days, I feel like such a failure."'
Una said that after expressing three ounces of milk she felt instant relief, adding that she doesn't think new mums should be put under any pressure to breastfeed.
"No woman should ever feel pressured or that she is a failure if she doesn't breastfeed. But just for the purity of that bond you feel with your baby, I'd say to any new mum, 'Just try it'," she said.
Una and Ben also explained their reasoning behind choosing the traditional Irish baby name: Tadhg – pronounced Tai-g.
Ben said: "We were going over names for ages and I'd suggested Ty, which I really liked, when Una said, 'There's an Irish name that's very similar.' As soon as she said it, I thought, 'That's cool.' With Una being Irish and Aoife having a traditional Irish name, it seemed fitting."
Una added: "Tadhg is quite common in Ireland so when people go on about how hard it is to match the pronunciation with the spelling, I say 'Just think, every time you say it, you're learning a new language and culture because you're speaking a bit of Gaelic."
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