Celebrities including Olivia Molly Rogers and Brittany Hockley have been documenting their egg freezing journey online.

Associate Professor Alex Polyakov said we are often told women are delaying their child-rearing years because of a corporate climb to the top, but it actually came down to two main factors.

One is age – with egg freezing recommended before the age of 35 for optimisation – and the other is having a partner.

Mr Polyakov, who is involved in fertility research, said: “Essentially we know that the majority of women delay child-bearing not because of travel or work, but because they don’t have a steady partner. That’s the biggest problem.

“That seems to be happening more often. And yes, I do think there is a lot of growth to be expected in this space for that reason.”

Hockley, 36, is in a long distance relationship with Swiss footballer Benjamin Siegrist, while Rogers, 31, is in a relatively new relationship with model Morgan Waterhouse after her shock divorce announcement late last year.

Both women, however, have been through the egg-freezing process before, in previous relationships or while single.

Rogers first underwent the treatment last year while married to ex-husband Justin McKeone, telling The Advertisershe expected this time to be “very different”.

“I’m feeling excited about it, I’m ready to do it but I’m also a bit nervy,” the 31-year-old said.

“I’m not so much nervous about the injections because when I was doing fertility treatments last year I was injecting myself everyday so I know I can do it, it’s just this is very different in terms of the amount of hormones.

“The treatment I was doing last year we wanted a maximum of two eggs … whereas this time around we want as many as possible … this time it’s a lot.”

Rogers said she was nervous about how her body would react, but hoped she wouldn’t be an “emotional wreck”.

In a July TikTok, Rogers said she’d made the decision to freeze her eggs to increase her chances of one day falling pregnant.

Meanwhile, Hockley has spoken about how she had to drop everything in her life to be able to undergo the process.

It’s not the first time she has gone through it – she was injecting herself with hormones two years ago.

Mr Polyakov said the average age of mothers currently is 30, with fertility declining rapidly at the age of 35.

Medical egg freezing is covered by Medicare and is a procedure connected to things such as chemotherapy or infertility but social egg freezing, which can cost between $5000 and $7000, is used by women who feel their biological clock is running out and they don’t have a partner.

Mr Polyakov said women would need to see a fertility expert and undergo a pelvic ultrasound to check for things such as ovarian cysts.

There is also a blood test, ovarian reserve testing and injections before the actual process of egg freezing begins.

But, there is also risks associated with the treatment, such as ovarian hyperstimulation syndrome. This is when a woman produces too many eggs during an IVF cycle, and that can land someone in hospital for “weeks”, according to Mr Polyakov.

According to IVF Australia, for women under 35 who collect 10 to 13 eggs, only seven to 10 would be viable for storage.

Only 80 to 90 per cent survive warming and of those eggs that survive only half to 80 per cent can be fertilised.

Of those that are fertilised, 80 to 90 per cent would develop into embryos. A single embryo would have just 20 to 35 per cent chance of developing into a pregnancy.

For those over 35, the results are significantly lower than those who are under 35.

Mr Polyakov said in theory, eggs could be frozen “indefinitely” but most states have legislative limits.

For example, in Victoria, you can only freeze eggs for up to five years but if you want them frozen longer you can get extension for another five years,” he said.

“After 10 years, something needs to happen to those eggs, either they get discarded or donated or used.”

One major issue is only 25 per cent of women come back to use the frozen eggs. Instead, the majority are discarded with only a handful donated to others trying to fall pregnant or to science.

Mr Polyakov urges those who are choosing not to use their frozen eggs to donate them.