A world-first trial is hoping to provide answers to patients who experience repeated failed attempts at IVF,

Hailed as a breakthrough, it will investigate whether the immune system could be a potential factor in unsuccessful pregnancies.

WATCH THE VIDEO ABOVE: World-first IVF trial hailed as a breakthrough

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Becoming a mother was not easy for Ria Miocevich, who endured seven egg collections, 11 embryo transfers, and a number of miscarriages and first trimester losses.

“It was heartbreaking and gut-wrenching at times,” Miocevich told 7NEWS.com.au.

Every round of IVF cost at least $15,000, but daughter Melena was worth every cent.

“Just pure joy. So much happiness. It’s life-changing,” Miocevich said.

Ria Miocevich and baby Melena. Credit: 7NEWS

It took Miocevich and her partner four gruelling years to fall pregnant, but she did not know why.

Now, a national trial aims to crack the embryo code.

It focuses on natural killer cells, a critical part of the immune system.

They help attach the embryo to the womb, but too many cells can impact implantation.

“Ten to 15 per cent of women are affected by recurrent implantation failure or recurrent miscarriage,” said Dr Rose McDonnell, a fertility specialist at Genea.

Simple blood test

A simple blood test will confirm if you qualify for the trial, being led by Genea.

Up to 1600 IVF patients are being recruited nationally for the trial, the largest of its kind worldwide.

It has already started in WA, with Sydney soon to follow.

“Patients like Ria can benefit from knowing ahead of time before the embryo is implanted if the natural cell activity or number is abnormal,” McDonnell said.

“And this will give them an opportunity to change the immune environment to facilitate implantation.”