Why more women carry the 'mental load' - and how couples can share it

"My head's always full," says mum-of-three Stacie Matthias. "I go to sleep with a mental to-do list."

She's talking about the concept of the "mental load" - the burden of planning, organising, remembering and anticipating tasks that keep a household running.

These tasks include: remembering school trips, checking for updates in parents' WhatsApp groups, noticing which parts of the house need cleaning, monitoring how much sleep children get, scheduling doctors' appointments and buying school uniforms.

According to academics, this is work that in heterosexual couples disproportionately falls to women - particularly mothers - alongside the bulk of physical household labour.

All relationships and households are different, of course, but studies suggest clear patterns.

Children in the UK have just gone back to school from the summer holidays, and Stacie, 37, from Stockport, says her mind often feels especially busy in September.

"It's that feeling of always having something to remember, organise or worry about that makes this time of year particularly full-on," she says.

For Stacie this list of responsibilities leaves her mind feeling like a washing-up bowl that's being filled up throughout the day.

"If someone's not helping you remove those pots and pans, your water's overflowing by the end of the day," she says, "and you're at tipping point."

In a survey looking into the mental load that involved 3,000 US parents, academics at the University of Bath and the University of Melbourne found that mothers handled 71% of household tasks that required mental effort, such as keeping track of when sheets and towels needed to be washed and remembering by when food in the fridge needed to be eaten.

The study found that fathers handled many of the tasks researchers described as "episodic" - things that happen less often, such as remembering when to get the car serviced.

University of Melbourne Prof Leah Ruppaner describes the mental load as being invisible, enduring and without boundaries. "You don't bring your dishes to work, but you bring the mental load everywhere," she says.

The mental load is a popular topic on forums like Reddit and Mumsnet, where women seek advice about how to talk to their partners about the exhaustion of trying to juggle so many different responsibilities.

Mums told BBC News they were often added to school WhatsApp groups - where parents discuss things like non-uniform days, school trips, birthdays and lost property - as the "default parent", while their partners never joined.

Sophia, a 35-year-old mum of three in Portsmouth, pays for........

© BBC