05/04/2015 16:32 BST | Updated 05/06/2015 06:59 BST

How Maternity Leave Can Destroy the Office Sisterhood​

Several friends recently forwarded me CEO Katharine Zaleski's blog on how poorly she treated working mothers before having one of her own. It was good to hear a woman admit her complicity in making women's lives a misery.

After all, no woman who's ever worked in an office thinks it's just guys who make life tough for working mothers.

But in my experience, the desk-bound sisterhood is severely tested well before women go back to work.

Nothing quite breaks the feminist bonds of a workplace like maternity leave.

I've personally covered two maternity leave shifts and played a supporting role in others. And in that time felt my desire to support women in their work/life balance slowly ebb away.

I didn't want to feel this way. But as these mothers-to-be left and returned, it became clear that pro-women work policies tended to work in one direction.

New mothers returning to the workplace instantly looked for ways to reestablish their authority - fast. And within days of their reappearances, I watched work done in their absence and my professional hopes go up in smoke.

There's no doubt that filling in for others when they take a leave of absence from a company is a career risk. You have to cross your fingers that jumping into a more senior job with little training might kickstart your career, despite there being no obligation to promote you once the term is done.

But what I did expect was an element of mutual respect from returnee mothers.

Some acknowledgement that just as these mums were working hard to maintain their professional progress, so was I.

Instead, I've watched my work discarded. I've seen longed-for roles 'disappear' in post-maternity restructures. And I've been been expected to alter my working patterns to accommodate the returning mothers' compressed hours. All of this without a word of consultation. And all at the express command of female managers.

Of I course I get it. It is their right to take control when they return to the workplace.

But this hasn't helped me feel better about my professional contributions being treated like a silly whim by the very women I had hoped one day to emulate.

I soon realised these women subconsciously knew that encouraging their deputies would threaten their hard-won chance of 'having it all'. It was something I could understand - but it didn't make the realisation any less depressing.

After I left one workplace, I discovered that a former colleague asked for the same flexible working hours as her boss, when she became pregnant - and the answer was a very firm no. Apparently, that particular work/life balance, which my friend had helped make possible, was patent protected.

Is it any wonder that working mothers feel isolated in the office, when such heavy-handed defensive strategies drive away the very support they should be fostering? Namely, the next generation of working mothers.

These days I am a freelance writer. And five days ago I had a baby.

Hopefully when I have to jump in and cover myself in a few months time, I'll take the needs of my replacement into stronger consideration.