But her apprehension at how it would be publicly received swiftly departed as the gifts and notes arrived.
They included a handmade, “cheerful and imperfect” baby blanket from school students “made up of 24 squares, bright blocks of colour, each crafted with simple, uneven purl stitches”.
Emails also flooded into her inbox.
“In the 24 hours after the news broke, the person who managed correspondence for me said she’d never seen such an influx.”
Ardern recalls a memory lapse during a conversation with a woman where she forgot something minor. She laughed it off as a case of “baby brain”.
The woman didn’t laugh, her eyes were serious and her voice firm, Ardern says in her book.
The woman told Ardern: “You absolutely cannot say that”.
“She was warning me: if you give your opponents any opening whatsoever, they will use your pregnancy to say that you – or any woman – shouldn’t be given a position of authority.”
Ardern says from then on, she treated her pregnancy like a test or a “set of hurdles to get through without breaking a sweat”.
And so she did, pushing through the pain of her feet swelling at a press conference in the Pacific.
“Rather than wrap things up, I kept going until there were no more questions, long after the time available had passed,” she says in the extract published by the Guardian.
“Only then, when I was certain I hadn’t been the one to cave, I hobbled away to shove my feet into a cold bath.”
Ardern gave birth to baby Neve in June 2018.
While in London for Commonwealth heads of government meeting (Chogm), she had a meeting with Queen Elizabeth.
“She had, of course, raised children in the public eye, so in our private meeting I asked if she had any advice. ‘You just get on with it,’ she said simply. She sounded so matter of fact, just as my grandma Margaret might have.”
In her valedictory speech at Parliament, Ardern, adorned in a kākahu, said she hoped she had shown people that you can be anxious, sensitive, kind, a mother or not, a nerd, a crier and a hugger – and “you can be all of these things, and not only can you be here, you can lead, just like me”.
“I leave knowing I was the best mother I could be. You can be that person, and you can be here.”
Today, Ardern lives in the United States with her family. She received an honorary doctorate from Harvard University, where she leads a course in empathetic leadership.
She remains patron for the Christchurch Call, an initiative she started to eradicate extremist content online after the terrorist attacks.
International magazines such as Forbes and Time have ranked her among the world’s most powerful or influential leaders. Fortune named her number one of 50 of the world’s greatest leaders. And in a different vein, that same year, she had a flightless wētā species named after her.
But as she said during her final speech in Parliament, she is happy to be known as “Neve’s mum”.
“I wouldn’t have it any other way.”
A Different Kind of Power will be published on Tuesday, June 3.
An in-depth look at the memoir by the Herald’s Kim Knight will be published on June 2.
Read Dame Jacinda Ardern’s interview with award-winning feature writer Kim Knight on Tuesday.
Julia Gabel is a Wellington-based political reporter. She joined the Herald in 2020 and has most recently focused on data journalism.