"We decided on round five that that was going to be our last cycle, then we were going to look at doing adoption."
On the day for transferring embryos into her uterus, only one remained viable.
"That was the one that stuck, when we had basically given up."
Madison, the first of the couple's children, was born in July 2007.
They went on to their sixth cycle of IVF. Two embryos were transferred and Mrs Horne became pregnant with twins, but lost one embryo between eight and nine weeks.
Brooklyn was born in April 2009.
The first two IVF cycles were state- funded; the rest of the treatment cost them at least $65,000, said Mrs Horne, 39.
Researchers from Otago University, Auckland University, Fertility Associates and colleagues in Britain and Spain have developed an experimental test which can detect the optimum time for an embryo to implant into the lining of the uterus.
If the test proves effective in further research, it could become commercially available within several years as a common addition to IVF treatment.
Mrs Horne, a marketing manager, said she would have used such a test if it had been available to her.
"When there's so much on the line financially and emotionally and you've got that one extra indicator to say, 'Hey, things are not ideal now, let's wait for next month', absolutely I would.
"If it saves wasting what could be great embryos that potentially might work, I think it's fantastic."
She said the emotional effect of repeatedly becoming pregnant only to miscarry was horrendous.
"The treatment is harsh enough as it is. Then you fall pregnant and I would always have two or three months of feeling sick. Then I would find out I had miscarried, which takes you another month to get over physically, let alone emotionally trying to pick yourself up off the ground.
"Then you have to get your body right again before you do another cycle, and get your head right too.
"The worst thing is that once you have had one miscarriage, you are just constantly on edge and the anxiety is massive ... a constant dread.
"I never felt I could celebrate my pregnancy, ever."
Q&A: Finding the right time to implant crucial for success
What is the problem?
In up to half of cases where a woman does not become pregnant following fertility treatment, the cause may involve the receptiveness of the lining of the uterus.
With IVF (in-vitro fertilisation), hormone medications are used to stimulate the ovaries to release eggs for artificial harvesting.
The medications can alter the rate at which the lining of the uterus reaches its optimum degree of receptiveness for successful implantation of embryos (fertilised eggs).
This can put the timing of the uterus out of sync with the timing of the embryo's development by up to several days.
What is the new test?
A research group has developed an experimental test that might help if further research supports the initial findings.
It involves taking a tiny tissue sample from the uterine lining and checking its protein expression.
This can precisely determine if the uterine lining will be receptive to the implantation of an embryo.
How could the test be used?
If the test showed the uterine lining of a woman undergoing IVF was not at its peak of receptiveness, the embryos, instead of being put back, could be frozen for future use.
They could be thawed and transferred at the optimum time during a later, natural fertility cycle or during a medically induced cycle.
The test could also be used to help diagnose if uterine problems were the cause of an IVF woman's repeated miscarriages or failure to become pregnant.
Will the test be developed further?
So far the research has involved fertile women. The researchers now want to include more of them, and women who need treatment for poor egg production, those who have had repeated unexplained miscarriages and women who have IVF without becoming pregnant.
Women aged 20 to 37 who wish to take part can call 0800 4 FERTILITY.
When might the test become commercially available?
It could be a few years, depending on the success of further research.
