Celebrities give birth in their late forties. But don’t assume you can too.

In 2014, 49 year old actress Laura Linney welcomed a baby son, her first child with husband Mark Schauer. The couple married in 2009 when Linney was 45.

Falling pregnant in your forties – let alone 49 – is exceedingly rare. Except in Hollywood where it seems to happen with extraordinary regularity.

A few months ago, Halle Berry gave birth for the second time aged 47, to her daughter, Nahla.

Kelly Preston had her third child in 2012, age 48. Susan Sarandon had a baby at 46, and Beverly D’Angelo had twins (with 65yo Al Pacino) at 49. Holly Hunter also gave birth to twins at the age of 47. Geena Davis had her twins at 48, Jane Seymour had twins at 45, Marcia Gay Harden and Desperate Housewives’ Marcia Cross both had twins at 45 and Cheryl Tiegs had twins at 52.

The unspoken question of course is how. How did these women become pregnant so late in life when statistically, the chances of conceiving are miniscule if not zero? According to doctors, pretty much the only way to become pregnant in your mid to late forties is by using donor eggs.

Understandably, celebrities rarely announce the way they became pregnant unless a surrogate was involved (like with Nicole Kidman and Sarah Jessica Parker). When you’re famous, it’s impossible to hide the fact you weren’t pregnant. But something that is possible – and easy – to hide is HOW you became pregnant.

So how do so many famous women become mothers in their mid to late forties and even into their fifties? Donor eggs.

“Celebrities may be different from you and me, they may be better looking but one thing they’re not is more fertile” a Beverly Hills doctor told US Elle magazine. This doctor has helped several middle-aged stars have babies with donor eggs and describes it as the last taboo of infertility.

Famous or not, the most common cause of infertility in women is age. Too many of us simply leave it too late – for a whole bunch of reasons. Sadly, after a certain point there’s nothing you can do to increase the number of eggs you have or extend their expiry date.

“The chance of an egg resulting in pregnancy declines as a woman ages,” explains Brisbane obstetrician/gynaecologist Dr Brad Robinson. “The reason for that is that eggs age just like every other part of us. So an old egg that is finally released at the age of 45 may come out of the ovary – but as I like to tell my patients – it may well come out on a zimmer frame. This is evidenced by the fact the miscarriage rate climbs as we age from 12% at under 30 to 51% at ages 40-44.

The other problem for older mums is that the risk of chromosomal abnormalities also rises exponentially as women age. For example Downs Syndrome – a woman aged 20 has a risk of down syndrome of 1 in 1500. A woman aged 43 has a risk of 1 in 45.”

One of my friends had IVF a few years ago when she was 33 and was shocked to discover her fellow patients in the waiting room were all in their mid to late forties. “They looked visibly desperate,” she remembers. “It was so sad. I felt like saying ‘go home, save yourself the heartbreak.’ How could they believe anything would make them pregnant at that age? Then I picked up a magazine to see Geena Davis pregnant at 49 and I suddenly understood.”

This is a frustration that doctors on the frontline of infertility face every day. “A pregnant actress in her forties gets a page in a magazine,” says Dr Ric Porter, director of IVF Australia. “But if those same magazines printed all the stories of all the women who couldn’t get pregnant, the magazines would be the size of the yellow pages. These celebrity ‘miracle pregnancies’ give women ridiculous expectations. I’m yet to see a patient who had viable eggs in her mid forties. Even with IVF, we’ve never had a pregnancy after age 45”.

To overcome this, some older women are electing to use donor eggs, confirms Dr Robinson. Donors are typically aged in their 20s and 30s and this changes the odds of the pregnancy remarkably. A woman aged 46 using her own eggs in IVF has at best a less than 3 percent chance of an embryo transfer actually resulting in a live birth. But if she is using donated eggs – from a younger woman – the live birth rate per episode is over 40 percent.”

My sister-in-law Nicky spent a long time trying to conceive. She was 40 when she first began the process but despite years of IVF, it wasn’t until she went to Greece in 2012 and used donor eggs that she was able to fall pregnant. With my adorable nephews who are now 10 months old.

She won’t mind me telling you this. She’s always been open and candid about her journey to become a mother, writing about it here on Mamamia several times and letting me interview her in this video series I’m doing with Nissan about Modern Families.

And this is where obstetricians, gynaecologists and fertility specialists can become enormously frustrated. Every time it’s announced that a celebrity like Laura Linney has had a baby around the age most women’s bodies are preparing for menopause, it sparks a wave of publicity and a tsunami of hope and delusion among the wider population who believe they too can conceive at 49.

Look, no woman is obliged to tell the world how she got pregnant, famous or not. Infertility is an intensely difficult, often painful and always personal experience.

But to safeguard our own fertility and our self-esteem, we need to start filtering these “miracle” celebrity pregnancies through a reality-check. Which brings us back to Hollywood’s donor egg explosion.

Dr Brad Robinson says he would welcome more honesty from celebrities about the realities of falling pregnant ‘naturally’ in their late forties. “These celebrities might be prettier, and wealthier than the rest of us – but their ovaries and eggs don’t age any differently” he says. ” They can have all the plastic surgery, all the vitamins and detoxes they like but that fact does not change.”

Socially, we’ve happily redefined our expectations of 40 but there’s no such thing as botox for your ovaries. Even in Hollywood.

So while every woman has the right to complete privacy around her fertility, remember that ‘miracle’ might not quite mean what you think…..