"It's really inspiring ... having our prime minister lead by example is a great sign of how far we've come in women's industrial rights in New Zealand," Council of Trade Unions President Richard Wagstaff said.
Former prime minister Helen Clark wished the couple "all the best" ahead of the expected birth in June. "Every woman should have the choice of combining family and career."
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Clark wasn't the only one to indicate that Ardern's decision had implications for regular woman.
"I know these are special circumstances but there are many women who have done it well before I have"
New Zealand National Council of Women CEO Gill Greer told NBC News that her organization would "like to see every woman in New Zealand having the choice to have a family and a career — or both, or neither — without prejudice or judgement. We wish them all the very best for the future.”
Fellow mother and politician Kiri Allan called it "the best news ever," adding that Ardern's baby would join the "growing sproglet contingent" in the country's parliament.
Sophie Walker, the leader of the U.K.'s Women's Equality Party, congratulated the couple, adding she hoped the news would serve as an example to others.
“We hope that this will encourage companies and governments around the world to consider what they can do to make sure their parental leave policies do not force women to choose between work and family,” she said.
Speaking to reporters outside her Auckland home Friday, Ardern said Gayford would care for the "surprise" addition full-time and that the whole family would travel together when necessary.
Ardern became New Zealand's third female leader on Oct. 26, after a surge in the polls catapulted her to power.
She said Gayford “will be ‘first man of fishing’ and stay-at-home dad,” a reference to his TV angling show.
Ardern said she discovered she was pregnant six days before she became prime minister.
When asked by how she had dealt with morning sickness while pulling together a government, she replied, "it's just what ladies do."
"I am not the first woman to work and have a baby. I know these are special circumstances but there are many women who have done it well before I have," said Ardern, who is the daughter of a police officer and school cafeteria worker.
The amateur DJ, who has performed sets at music festivals in New Zealand since being elected as a lawmaker in 2008, was raised a Mormon but left the church.
She has previously discussed the dilemmas faced by women pursuing a career who also wanted to have a family.
Soon after taking the helm of the Labour Party in August, Ardern was asked whether she had to choose between the two.
She clashed with journalist Mark Richardson, pointing a finger at him and saying it was “totally unacceptable in 2017 to say that women should have to answer that question in the workplace.”
New Zealand has a track record of firsts when it comes to women. In 1893, it became the first country to give women the right to vote. Women were not allowed to vote in the U.S. until 1920.