Jacinda Ardern will not be the first woman to give birth while in office - almost 30 years ago the Prime Minister of Pakistan gave birth to her second child while in power.

Ardern has just announced she is expecting her first baby in June this year.

Twenty-seven years ago, then prime minister of Pakistan, Benazir Bhutto gave birth to her daughter Bakhtawar on January, 25 1990, and was reportedly the first modern head of government to give birth while in office.

Her first-born, Bilawal, was born on September 21, 1988, mere weeks before she took office in December 1988.

Her third child, Aseefa, was also a just a few months old when she assumed office for the second time in October 1993.

The current Queen of the United Kingdom, Elizabeth II, had two of her four children during her reign - Prince Andrew and Prince Edward.

Andrew was born in 1960, almost eight years after she took the crown in December 1952.

Her eldest Prince Charles would have been almost four at the time, and her second born, Princess Anne, would have been almost two.

Further back in history Queen Victoria had nine children during her reign from June 20 1837. Her first child, also Victoria, was born in 1840 and her youngest, Beatrice, was born 17 years later in 1857.