In one sentence, The Simpsons issues a typically sharp and bang-on riff on the zeitgeist, this time on the intense guilt and anxiety mothers feel about a job that is supposed to come naturally to them: being mothers. There's the overload of not-always-reliable information, the anxious marking of milestones and the massive industry that has sprung up around pandering to those anxieties, all of which mix in with hormones, exhaustion, and a sometimes fragile self-confidence.

As we gear up for another Mother's Day rife with sentiment and more pink slippers than you can poke a bunch of flowers at, the question is where this "mother guilt" - as it has been coined - comes from and what we do about it. And does the mass romanticising of mothering - the maternal ideal so often seen in advertising and popular culture -- help to create an unrealistic idea of motherhood that sets up women to fail?

The guilt hits early, and often. From the time you get the two blue lines on the pregnancy test, countless books, friends, relatives and passers-by will offer information and lightly-coded instructions on how to raise your little batch of dividing cells. Don't drink, don't go near the wrong cleaning equipment - my god, is that coffee? - watch out for the sushi and the goat's cheese and for heaven's sake don't pick up any cat poo because you can't be too careful with toxoplasmosis. This is not to say these don't have genuine risks, of course, but they are probably out of proportion with the alarm that accompanies them.

Then there is the birth itself - a caesarean, eh? oh, that's a shame - and the breastfeeding or - tsk - bottle-feeding, when to wean, the adequate amounts of "tummy time", the shift to wholesome eating, the meeting of milestones, when to return to work and how much childcare to employ.

These questions can leave new mothers feeling stricken with anxiety, worried that they are inadvertently causing harm to their babies and unable to trust their own instincts and good sense. And while all of this is tossed into a whirlpool of raging hormones and too little sleep, they're expected to behave as though they're having the time of their lives, and coping just fine.

A friend of mine, having a hard time with a fractious nine-month-old, her partner working late and the temporary loss of the support she usually had around her, found herself dissolving into tears of exhaustion and frustration in front of her GP.

"Oh," said the doctor, "you're not enjoying motherhood very much, are you?"

It may have been meant sympathetically, but like a lot of things around early motherhood, simply sounded judgmental and made my friend feel terrible.

"Everyone does feel the expectation that you have to be happy all the time, "says Age columnist Monica Dux, author of Things I Didn't Expect When I Was Expecting and editor of Mothermorphosis, and that in turn can leave women feeling isolated, alone and, of course, guilty.

The truth is that no matter how much you love your children - and in some ways the frustrations of motherhood have nothing to do with how you feel about the children themselves - there will be days, hours, moments when it's lonely, frustrating, maddening or boring. But women often feel they cannot say that, for fear of being branded a bad mother.

"I think all women feel at times that they've failed as a mother," Dux says. "We don't often talk about the ugly side of motherhood, like with newborns and the absolute despair that we can feel."

Pinky McKay sees mother guilt take a hold of women all the time. Having been around new mothers as a lactation consultant for about 30 years, written several books on early parenting and raised five children herself, she has no doubt that it is a real and powerful phenomenon.

"The self-doubt is really huge," she says. And it has certainly far more prevalent than it was a generation ago."We have a lot more access to information now which is a good thing but it also is a double-edged sword where we start to question ourselves a whole lot more."

It does seem to be a peculiarly female phenomenon too: McKay has never come across "father guilt", mostly, she believes, because men tend to take a more practical view of their parenting role (it is probably also because mothers still tend to do the bulk of the early rearing).

Women also become mothers at very different stages in their lives these days. We settle down later, we are having babies later - often in our late 30s and even 40s - and we have often had many years of independence, freedom and achievement  before we do so. Then overnight, that all changes, and it is a huge shock to the system, especially as many of us have had little to do with newborn babies.

So we read our books and go to classes and do all the things we're meant to do. But the trouble is, babies are little individuals who, at least to some extent, will do their own thing, and parents have to bend with them.

"Surrender" can be a difficult term for new mothers to come to grips with, McKay says. "Particularly women who have been high-achieving in their careers and able to control the outcomes," she says. "With a baby, it's not just a piece of clay that you can mould."

Media icon Ita Buttrose knows a bit about mother guilt too. In 2005 she and Dr Penny Adams co-wrote a book by that title, having noticed how prevalent it was among new mothers in particular.

She believes that the high expectations society places on mothers puts a huge amount of pressure on women. Yes, there is the surfeit of information to contend with, but a new mother must also managing an interrupted career and the sudden, dramatic adjustment to life as a mother.

Along with anxiety inevitably comes competition. "They go to those mothers groups, which seem very judgmental to me, some of them, and they compare," Buttrose says, which in turn often simply fuels their anxiety, because babies all develop in different ways and at different paces, little of which has any meaning for their future success and happiness.

"Maybe to a great extent we've just lost the joy of mothering," she says. "It seems to be very difficult just to accept the way it is and realise that these are just passages of life."

Dux believes one of the problems we have is our inability to see mothers as complex, flawed people - instead we hang on collectively to a Hallmark version of the maternal ideal. Mother's Day brings this into sharp focus: it does not make any room for people who have fraught relationships with their mothers, for example - instead, it's big love (and big spending) all around.

"When you become a mother, you're not actually a person, you're a symbol," she says.

Mother guilt also has a strong commercial underpinning. The ABC's The Checkout has very cleverly parodied this in its "as a guilty mum" segments, such as: "As a guilty mum, I know when baby won't sleep it's not Mother Nature's fault, it's my fault." Cue a host of equipment you can buy to ease baby's imperfections.

Buttrose also rails at all the classes purporting to develop very young children. "We're not breeding Einsteins here, we're breeding children, and children need to be children: they need to have time to rest … they don't need to adopt our busy lifestyles."

What to do? Well, Buttrose has a neat solution: relax. Don't take it all too seriously.

Perhaps mothers also need to look for and find support where they can - other mothers you like and trust are great for this - and shake off the ones who are competitive and judgmental.

And, says, McKay, just know that not everything comes as naturally as you might be led to believe - hello, breastfeeding - and that your (largely) happy little person is evidence that you're doing a good job: "It's just accepting that whatever you're doing is enough, and that you are enough, as a mother, for that child."