She has honed the physiques of "supermums'' Gwyneth Paltrow, Jennifer Lopez and Madonna, so when the celebrity trainer Tracy Anderson whipped herself back into shape only six weeks after giving birth – by caesarean section – to her daughter, Penelope, it was a fitting advertisement for her exercise DVD, The Pregnancy Project.

However, it was also yet another crushing blow for new mothers all over the western world: women who weeks, months or even years after giving birth still bemoan their sagging, stretchmark-covered mummy tummies. In mother and baby groups and NCT get-togethers across the UK, thousands of women are still wearing maternity jeans six months after giving birth.

There will also be one or two women who have shed their baby weight, the disciplined souls who have poured their yoga-honed midriff into a body-skimming Breton top and skinny jeans. Just like Anderson and her high-profile clients, these are the women who have bounced back into shape within a nanosecond – making everyday mothers feel like flabby, frumpy, frazzled failures.

Writing in the New York Times last week, Janice Min described how – four months after giving birth – she was humiliated when her manicurist asked when her baby was due. "First, I'm irked. Then embarrassed," wrote Min. "I pushed out a 6lb 10oz baby girl nearly four months ago. And I'm 42 to boot. Can't I get a free pass?"

The majority would sympathise with Min's plight: after all, many of us had to breathe in and make light of such an awkward situation. But then it transpires that Min is not one of us. She is the former editor-in-chief of celebrity gossip magazine US Weekly: under her reign, between 2003 and 2009, its circulation grew from 800,000 to 1.9m and she pocketed a reputed $2m a year salary. She defined her formula for publishing success: "As the editor of US Weekly, covering the Suris and Shilohs of Hollywood for six years, I delivered what the young female audience wanted: cute moms and babies."

So, as she rightly points out in her New York Times piece, she is "partly to blame" for the culture in which we live, where everyday mothers are bombarded with a daily diet of celebrity mothers and their beautiful bodies. In fact, in typical 21st-century fashion, a trendy hybrid label has been coined so we can recognise these glamorous supermothers: the momshell (mom and bombshell – geddit?).

"These genetic aberrations smile at us from celebrity magazines, or from our computer screens, wearing bikinis on the beach in Cabo weeks after caesarean sections, or going straight from recovery room to Victoria's Secret runway," Min wrote.

Cue the backlash: the blogosphere has gone mad. What right does this woman have to complain about the monster she created? Even the Christian Science Monitor got in on the act, pointing out with more than a hint of cynicism that Min has just written a book, How to Look Hot in a Minivan: A Real Woman's Guide to Losing Weight, Looking Great and Dressing Chic in the Age of the Celebrity Mom.

But Min does have a point, however hypocritical it is to make it. In the internet age, we cannot avoid being inundated with images that, even subliminally, make us feel inadequate if we boast so much as a muffin top at toddler group.

Gemma Beckers gave birth to her first baby, Lena, on 10 August and only three weeks into motherhood she admits: "I worry more about my appearance now than I ever did before I was pregnant. Now I find myself comparing how I look to other new mums, like it's some gauge of how we're coping with the rollercoaster journey." The 29-year-old fashion buyer from Hove, East Sussex, confesses she is addicted to celebrity gossip magazines, but acknowledges, "they never show the chef, the nutritionist, the personal trainer, the nanny, the housekeeper, the beautician and all the other staff required to get those Hollywood mums looking photo-ready. I'm flabbergasted to see celebrities who've carried a baby full term and then parade in a bikini after a month."

Professional cellist Emma Black, 43, mother of Maya, 5 and Lotte, 2, from Great Missenden, Buckinghamshire, feels the momshell culture "is pernicious and damaging to women. I am that bit older. I was 38 when I had my first baby, and I think that helps because I am more comfortable in my own skin, but you need to have a robust sense of self not to be pulled in by the constant stream of 'perfect' celebrity images.

"It makes me desperately sad to see mothers lacking confidence because they don't look a certain way, or talking about weight loss when they've just given birth. It takes away from the joy of motherhood."

There are, of course, those rare beings who shed the pounds rapidly. "I am naturally thin and was taken aback by how quickly the weight came off – without effort - after having my daughter (now seven), so I was back in my skinny jeans within days," says Jo Elvin, the Australian editor of Glamour magazine. "But I am really disturbed by this phenomenon. The celebrity thing has got so out of hand and we are studying them in microscopic detail: obsessing over how someone looks, after giving birth especially, is so unhealthy."

Psychologically, the impact of a glossy, glamorous supermodel in a designer bikini cradling her newborn in St Barts is one that can really send a hormonal, sleep-deprived, first-time mother into hiding with only her husband's pyjamas and dressing gown for company.

It certainly doesn't help when models such as Heidi Klum, Gisele Bundchen and Miranda Kerr snap back to their svelte pre-pregnancy shape before their offspring have got through their first pack of disposable nappies. Or when Victoria Beckham appears at New York fashion week in one of her bodycon frocks, hugging the newborn Harper Seven. Or again when Beyoncé drops 60lb within weeks of delivering daughter Blue Ivy, crediting "cardio and sculpting sessions five days a week, plus tour rehearsals" for the weight loss.

And let's face it: if you didn't look like a Victoria's Secret angel before gestation, you sure as hell aren't going to look like one after giving birth.

Tim Weeks, a former Olympic coach who now works as a personal trainer specialising in women's fitness and wellbeing, points out that exercising too soon after giving birth is far from ideal. His GP wife, Yasmin, presented him with a son, Rafi, eight weeks ago and he insists she should only now be starting very gentle swimming or yoga. "You need to look at giving birth like major surgery, even if you have a natural birth. If you have any kind of surgical procedure, you would have a rest period, then a slow rehabilitation period, then a proper recovery period. Your body has gone through massive physiological changes, and it's not just a matter of doing a few sit-ups to fix a flabby tummy – you need to rebalance all the elements, which is a long, slow process. You need to look at cardiorespiratory fitness, structural strength and posture, nutrition, rest and recovery and your psychological wellbeing."

"Your hormones are all over the place, your body has dealt with another human being growing inside you, then pushed it out. I don't let any of my 'new mum' clients do any exercise, other than a gentle stroll with the pram, for six weeks. Even if they are superfit, Olympic-standard athletes, they would expect a rest and recovery period after an 'injury': this is the same."

His views are echoed by Michael Dooley, a specialist sports gynaecologist, who acted as senior gynaecologist at the London Olympics. "Every woman is individual and you must listen to your body. If you are used to being in control of your life, you have to accept that you have to relinquish that for a while. Your life has been taken over by a demanding baby and there will be pressure from all areas to make you feel you are not doing things right, or you haven't snapped back into shape quickly enough. But it takes time, so take time. I think it takes a year for your body to fully recuperate from the physiological changes in pregnancy, so set smart, achievable targets."

Thankfully, a handful of high-profile women are happy to follow this path. John Travolta's wife, the actress Kelly Preston, 49, said she refused to rush her weight loss after giving birth to Benjamin in 2010. "I actually took my time purposely because I really wanted to. You can do it much more quickly," Preston told Good Morning America. "I'm not into the three to four weeks. But I did it over the course of eight months."

Bollywood beauty Ashwarya Rai was cruelly lambasted for not shedding the pounds after the birth of her daughter in November 2011, but claimed that she wanted to focus on her baby before turning the spotlight on her own wellbeing.

The BBC2 radio presenter Janey Lee Grace, mother of four children and author of Imperfectly Natural Woman and Imperfectly Natural Baby and Toddler, says: "In an ideal world, you would have a babymoon where you put your feet up and look after your newborn, while your friends and family look after your home and cook."

In fact, in some Asian cultures – China, in particular – the practice of confinement is still popular, with some "postpartum houses" cropping up to cater for immigrants in US cities, using doulas in the place of relatives to support new mothers. Though it may seem outdated to many modern western women – it was common in Victorian times in the UK – there may be something to be said for the idea of focusing on bonding with your baby while being looked after by others, away from public scrutiny and exposure to celebrity momshells.