The 'What About Us' singer and her rugby playing husband Ben Foden became first-time parents in 2012 when Una gave birth to their daughter Aoife Belle.
She was the first of The Saturdays to become a mum, followed by Rochelle Humes and Frankie Sandford earlier this year.
Speaking in the new issue of Cosmopolitan Body, Una said: "I was very broody immediately after Aoife's birth, and even after meeting Rochelle's little girl Alaia-Mai. But now I'm just enjoying Aoife being young.
"I'm excited for The Saturdays to go on tour in 2014, so Ben and I aren't thinking about having another baby just yet…"
Irish-born Una frequently posts pictures of her gorgeous daughter on Twitter and says she's hoping Aoife will take after her sporty dad parents as she grows up.
In addition to being a competitive swimmer when she was younger, Una will be showing her athletic side in the new series of Tom Daley's Splash!, which premieres January.
"I'm hoping that Aoife will take after Ben and me when it comes to sport. I was very active as a kid (I used to swim competitively growing up and, like me, Aoife has no fear of water) plus Ben's very sporty and speedy, obviously, so I think she'll be quite fast on her feet. I will definitely encourage her to do sport as it's great for building confidence."
Cosmopolitan Body, Cosmopolitan's health and fitness spin-off magazine, is on sale 27 December. For more information visit www.cosmopolitan.co.uk/UnaCosmoBody.