This makes her only the second world leader to have a child while in office.
New Zealand Prime Minister Jacinda Ardern gave birth to a baby girl on Thursday, the first world leader in nearly 30 years to have a child while in office.
In a post on her official Instagram account, Ardern said the baby arrived at 4.45 pm local time, weight 3.31 kilogram (7.3 pounds).
Admitted to the hospital earlier in the day, Ardern’s expected due date had been June 17.
The 37-year-old has now passed on her duties to the Deputy Prime Minister Winston Peters. She has said she will take six weeks of maternity leave.
Ardern, who was elected in October, announced in January that she and her partner Clarke Gayford were expecting a baby.
“I am not the first woman to multitask. I am not the first woman to work and have a baby; there are many women who have done this before,” she had said earlier this year in an interview with Radio New Zealand.
She is the youngest prime minister the country has had since 1856.
In 1990, Benazir Bhutto gave birth to a daughter while serving as Pakistan’s prime minister, a first for an elected world leader.