The shock resignation of New Zealand Prime Minister Jacinda Ardern, who altered the face of global politics when she was elected the world's youngest female head of state, throws a spotlight on the demands faced by women in power.
Holding back tears as she made her declaration, the 42-year-old said she had next to nothing left "in the tank" and it was time to step aside after a challenging 5-1/2 years in office.
