Congratulations to New Zealand’s prime minister, Jacinda Ardern, who’s expecting her first child with her partner, Clarke Gayford, a “stay-at-home dad”.

Although she won’t be the first world leader to give birth while in office (Pakistan’s prime minister Benazir Bhutto did so in 1990), perhaps Ardern could help prove that politics isn’t incompatible with new motherhood. (And, if it is, perhaps it’s politics that needs to change.) While campaigning, Ardern defended a woman’s rights to privacy about her baby plans and says now that she’ll take six weeks’ leave, while remaining “contactable” – and that, anyway, mothers are no strangers to multi-tasking. Quite.

Ultimately, Ardern’s main obstacle could lie in the general chauvinism towards powerful women and motherhood. When male political leaders, such as Tony Blair, become fathers in office, it’s traditionally viewed as a sign of potency. A prime minister who isn’t just kissing babies but also producing them, from his “mighty loins”, is viewed as an alpha-papa figure.

By contrast, with powerful women – in politics and elsewhere – having babies swiftly becomes a negative, with endless question marks over their competence and focus. Even today, in business, the faintest suspicion that a woman may one day want to become a mother could be held against her, just more covertly than before.

Rachida Dati returning to work after a mere five days was, to me, a paranoid expression of job insecurity

This then leads to another workplace syndrome, whereby motherhood is turned into a bizarre, quasi-macho “pissing contest”, revealing itself in how little maternity leave a woman may take. In 2009, France’s then justice minister, Rachida Dati, returned to work a mere five days after having a caesarean, which, to me, rather than being an act of strength, was a paranoid cowering expression of job insecurity.

While some women simply don’t want to be mothers, others, like Dati, seem determined to prove that they can condense the whole thing into an ultra-manageable timeframe. Why? Because women have long been given the message that motherhood wrecks careers. It’s a suspicion that is underlined in the UK by the continuing male reluctance to take extended paternity leave. It’s as though men fear being treated differently – and by “differently”, I mean like women.

Sometimes neither partner can afford to take extended parental leave, usually for financial reasons. Moreover, in her situation, it would be nigh on impossible for Ardern to take significantly more leave – and unlike many professional women, she has a partner at home.

However, she could continue doing her bit to undermine the enduring toxic fallacy that motherhood somehow derails female professionalism. She’s already publicly blasted the notion that anyone has a right to interrogate women about their baby plans. Now Ardern could prove that it’s possible to juggle pregnancy and motherhood with a top political job. Along the way, she could quietly demonstrate to women the world over the correct way to use maternity leave – take as much as you really want and need and do so entirely unapologetically.