Just a handful of elected leaders worldwide have given birth while in office, notably Benazir Bhutto, who had her son in 1990 while prime minister of Pakistan.
The yet-to-be-named baby girl was born on Thursday afternoon, weighing 3.31 kilograms.
Jacinda Ardern has given birth to a baby girl.
Ms Ardern's pregnancy had prompted widespread debate about working mothers - some championing her for breaking new ground while others questioned her ability to work with a newborn.
"It's wonderful", she said.
"These events and the way our country has greeted them will be seen as inspirational by all who advocate for gender equality and women's empowerment", Ms Clark said. Asked by reporters if she had made a choice, Ardern said the process was going "terribly", per The New York Times.
Phillies fan injured when Phanatic shoots hot dog into stands
Who knew a hot dog could be so unsafe ?? "And mostly, it's going to get worse before it gets better". It's unclear if the team plans to make any changes to its hot dog launcher stunt.
Prior to her, Queen Elizabeth II gave birth to Prince Andrew in 1960 and Prince Edward in 1964 after her ascension to the throne in 1952.
"Can I extend very best wishes to all the family at this very happy time", Mr Peters said.
Deputy Prime Minister Winston Peters has now taken over as acting prime minister. Ardern plans to take six weeks of leave before returning to work.
The story was the most read on The Guardian, and the site shared an opinion piece by former Prime Minister Helen Clark, titled "Jacinda Ardern shows that no doors are closed to women.". "Thank you", Ms Ardern said in a statement.
Time to Tune in for Some IGTV — Instagram
Karen Leung expects to try it for an account she runs devoted to her 5-year-old Shiba Inu named Nacho , which has 7,000 followers. Instagram chief executive Kevin Systrom announced the milestone as he unveiled the new video application known as IGTV.
Ardern's partner, Clarke Gayford, will be a stay-at-home father.
The 37-year-old has now passed on her duties to the Deputy Prime Minister Winston Peters.
Ardern became Prime Minister of New Zealand last October, after forging a three-way coalition only several months after taking the reigns of the Labour Party.
Ms Ardern has remained hard at work during the course of her pregnancy, and news of the child was celebrated worldwide when she announced she was due to give birth.
"I also think there are women every day who manage of all of these things - I just manage to do my job in a public way and I happen to have probably more people than most around me supporting me".
China: ‘Capricious’ trade policies will hurt United States workers
And the EU's trade chief Cecilia Malmstrom said she was "very worried" the row with Mr Trump could trigger a "full trade war". Canada's retaliatory measures begin on July 1, and Mexico and other nations have also announced they will respond.