Blue hoped the sharing of childcare and work responsibilities became the norm for Kiwi families as this would help gender equality and smash the pay gap.
"More men have to take on childcare responsibilities. And millennial men want to do it anyway.
"When men take on more responsibility it means women won't lose ground with their career."
Ultimately, after 26 weeks of paid parental leave came into force, Blue wanted to see men get paid parental leave in their own right, to help them stay at home and bond with their baby.
She said having a baby would add another dimension to Ardern as becoming a mum makes you look at the world "through a different lens".
"I'm so delighted. I hope everyone is wishing her well. That's what she needs, more support … She's going to be a wonderful mum.
"I bet at some stage, when she has the baby, she'll say the Prime Minister role is the easier job.
"These little people bring you to your knees. It's just very grounding."