Great expectations: Why are we as a society obsessed with "outing" celebrity pregnancies?

Is she? Isn't she? And is it any business of ours? What our obsession with celebrity mums-to-be says about us

Who hasn't had enough of Beyoncé's pregnancy already? She's not due to drop until February next year but already it feels as though we're awaiting the Second Coming. First there was the weird "announcement" at the MTV awards ceremony back in August. She unbuttoned her jacket, rubbed her belly and glanced coyly at her husband. The audience got it immediately and erupted into a collective barrage of screams. The happy news prompted a frenzy of 8,868 tweets per second, a new Twitter record – more than followed the death of Osama bin Laden or the earthquake in Japan.

Then, last month, Beyoncé appeared on an Australian talk show. According to global news networks, which lost no time in bringing us this important detail, as she sat down, "her baby bump appeared to deflate". Such physical catastrophe instantly prompted wild speculation that Beyoncé was sporting a prosthetic belly and was, in fact, faking the whole thing. Questions still fly to this day. Has she secretly employed a surrogate? Did she lie about the date of conception? Is she trying to enhance her bump? Should her boobs really look like that? And aren't those heels a little too high for a mother-to-be?

We've long made it our business to know everything we can about celebrities. First it was their homes and their weddings. Then it was their love lives and addictions. Now we have taken it one step further. Call it fertility fetishism, uterus watching or whatever you want – nowadays we want to know what's going on on the inside. As the respected online magazine Salon succinctly put it after weeks of speculation about whether another American singer is with child: "Get out of Jessica Simpson's womb."

You can see why tabloids and the proliferation of online celebrity websites love this pregnancy gossip. It makes for the perfect speculative story. It allows them to run a paparazzi shot of a celebrity alongside an "Is she? Isn't she?" tag. It looks like a story even if there is nothing to it and is standard cover material for Grazia or Heat, because their editors know the "bump shot" sells magazines. Witness, for example, the cover of American gossip magazine In Touch Weekly a few years ago. "Yes she's pregnant. Ultrasound!" the headline screamed over a picture of Britney Spears in a mini-dress. That baby has yet to materialise, but Britney's hardly going to bother suing over it.

And there have been plenty of real pregnancies for onlookers to feast on recently. There was Victoria Beckham, who was scrutinised from every angle in the press and then obliged us further by posting extra pictures on Twitter. There was January Jones, who hid her bump under thick jumpers and refused to reveal the name of the father. There was Carla Bruni-Sarkozy, who flaunted hers in a little charcoal bikini and declared her eagerness to get it all over with so she could get on with smoking again. And there is Sam Taylor-Wood, currently eight months' pregnant with baby number four with an angelic-looking man less than half her age.

"It's totally obscene, but we can probably tell you these celebrities' babies' names, including all middle names, quicker than you can recall your own cousin's baby's names," says the author Imogen Edwards-Jones. "These days a celebrity having a baby is almost akin to your own sister giving birth. We are obsessed."

And it's not just the pregnant ones that concern us either. A hand on the belly (Katy Perry at her recent O2 gig) or a little bloating (Lindsay Lohan) prompt a barrage of speculation that someone must be expecting. Then there are the celebrities we all assume are too anorexic or too vain to endure pregnancy, the ones we are convinced used IVF and the ones who aren't pregnant but, we think, certainly should be. That's you Jennifer Aniston (aged 42), the reigning queen of baby speculation, and you Kylie Minogue (aged 43), and you Katie Holmes, who should have been on to baby number two ages ago.

"The recent trend for media frenzy over whether certain famous women are pregnant or not is particularly gruesome," says Kate Smurthwaite of feminist website Cruella-Blog. "There are reasons why a woman might want to keep a pregnancy a secret, such as medical complications that might lead to miscarriage or termination. And, on the other hand, if these women are not pregnant and have merely put on a few pounds, or decided life's too short for control knickers, the speculation is downright rude. Whether it's complimentary or critical, the message is clear: women's bodies are public property."

This obsession reached another level last month when 36-year-old American artist Marni Kotak decided actually to give birth in front of an audience in a fashionable gallery in downtown Brooklyn. And for anyone who missed that spectacle, a video of the delivery was installed in the gallery afterwards. Kotak explained her behaviour by saying that giving birth is the "highest form of art there is". One spectator reported walking in to find the artist sitting there, "calmly eating a banana, the placenta in a bowl". Art definitely doesn't get much higher than that.

It all used to be such a different story. Pregnancies would be discreetly managed or even pass without mention. Audrey Hepburn took a year off work in the run-up to giving birth to her son, while Elizabeth Taylor simply took to her bed. "It never used to be something that was glamorised or fetishised," says Edwards-Jones. "In the 1960s everyone covered up. I'm not suggesting for one second we hark back to that – the idea of a confinement meant that you were confined; no one bothered to talk to you. But what used to be a family matter has now become a publicity matter. In their constant desire to sell records and clothing lines and perfumes, celebrities need to keep finding ways to keep themselves in the limelight. Babies and pregnancies are a good way of doing that. Wombs, it seems, are the new handbags."

Is Demi Moore to blame for all this? She started the trend when she posed nude on the cover of Vanity Fair in 1991 while just about to drop her second daughter. Pop stars quickly followed suit. First, All Saints' Melanie Blatt stepped out on stage sporting a stretchy top which rose up over her baby bump. "It's a child not a terminal illness," she said at the time. Then expectant Spice Girls Posh and Scary began sporting the tightest little garbs they could squeeze into. A whole new lexicon has since sprung up around the look. First there was the annoying, but essentially quite harmless yummy mummy. Recently that moved up a notch and now they are red-hot mamas. So much for girl power.

There is a clear feminist angle to all this – the constant objectification and speculation about women's bodies, especially their weight. "Poor old Scarlett Johansson was recently accused of being pregnant because she had actually made the mistake of having lunch," says Edwards-Jones. And as Salon puts it, "Our obsession with celebrity baby bumps reduces women to their uterus."

But worse is when these very public pregnancies go wrong. Amanda Holden, Lily Allen and Kelly Brook have all recently had to live through painful late-term miscarriages under the scrutiny of the tabloid press. The stories of their baby losses have, in some ways, become their defining ones. Lily Allen, now pregnant again, has done the sensible thing and disappeared off the radar, but poor old Amanda Holden, due at the beginning of next year – the subtext of every tabloid picture of her seems to be: will she be able to carry it to term?

"It's obviously really sad when you have to go through that kind of tragedy in front of the cameras," says Jamie East, owner of gossip site Holy Moly!. "But pregnancy is a very delicate thing and sadly things do go wrong. It sounds really callous, but I think you almost forfeit your right to be able to cope with it privately if one of the first things you do when you find out you are pregnant is organise a magazine spread. As sad and distasteful as that sounds, you can't bend the rules. Lily Allen is a very good example that you can just disappear off to have a baby. And she's probably a million times happier for it."

Meanwhile, our baby-bump obsession continues. In this month's issue of American Elle, you can read about Aniston, one of the most powerful women in Hollywood, having to answer yet more creepy, prying questions about why she still hasn't had a baby. "There's no desperation; if it's meant to be, it's meant to be," she told them, yet again.

On these shores a new flurry of celebrities – Billie Piper, Sophie Ellis-Bextor and Stacey Solomon – have all recently trumpeted their pregnancies (mostly by way of Twitter, the modern-day equivalent of placing an announcement in The Times), so are now ripe for months of public inspection. Goodness knows how all this is going to filter down to us civilians.

"The constant speculation about who's pregnant, who's having a baby, who's trying and who can't, is quite dangerous," concludes Edwards-Jones. "Recently we had Chantelle Houghton publicly talking about doing IVF, three months into a new relationship. What kind of message is that going to send? How all this mania is going to manifest itself in the real world is a great cranking up of the pressure. There is already pressure to get married and now there will be an immense pressure to come up with the goods immediately. It's a lot of false stories feeding into even greater false expectation."