Women who need medical help to become pregnant but face risks from standard IVF treatment are being offered new hope of motherhood.

The first baby from the technique, in-vitro maturation, was born in the United States in 1983, but "IVM" has just been permitted in New Zealand.

"To get it approved as a recognised treatment has taken seven, almost eight years," said Auckland fertility specialist Dr Simon Kelly, of Fertility Associates, which is introducing IVM following the Government green light a week ago.

One of his patients, Virinia Luhrs, 45, whose two standard-IVF boys were born in 2006 and 2009, had hoped to use the new technique when she became pregnant with her second baby, but she was three years ahead of the government decision.

Mrs Luhrs, whose family is living with her parents in Kirwee, west of Christchurch, after their city apartment was damaged by the earthquake, said she was rapt with the government decision, for which she had lobbied.

"I am thrilled that couples who do not have [standard] IVF as a treatment option because of the risks to their health now have an opportunity to become parents - one of life's greatest privileges."

In-vitro maturation is a variation of IVF in which immature eggs are collected. The hormone treatment to stimulate release of multiple mature eggs is omitted. The eggs are matured in the laboratory.

The new technique will mainly benefit the 20 per cent of sub-fertile women with polycystic ovarian syndrome, which causes multiple small cysts to form in the ovaries and makes it difficult for some to become pregnant.

IVM is a safer treatment for these women, who are at greater risk of ovarian hyper-stimulation syndrome, a usually mild - but potentially life-threatening - complication of IVF hormone treatment.

IVM is also offered to women who wish to avoid or do not have time to use hormone stimulation before starting cancer chemotherapy which may impair their fertility. Their eggs can be frozen for later use.

But it does have a downside. The pregnancy rate is less than with standard IVF, but is improving.

Dr Kelly said the IVM pregnancy rate was less than half that of standard IVF five years ago, but had increased to two-thirds.

He said the price would be similar to standard IVF - $10,000 to $11,000 for one cycle. IVM had higher lab costs, but omitting hormone treatment avoided drug costs of between $1500 and $4000.

Mrs Luhrs said she and her husband, John, had IVF treatment because of her age. She was 38 when they married, and his vasectomy reversal operation - he has another family from an earlier relationship - had worked only briefly, then failed.

One semen sample taken after the operation and frozen was sufficient to make the couple's two boys.

Mrs Luhrs had wanted to try IVM to avoid the IVF drugs because - between babies - she fell ill with a spinal cord inflammation that caused temporary paralysis of her lower left side and required treatment with steroids.

"If I could, I didn't want to have another round of heavy-duty drugs. They don't make you feel that great and they are costly."

The Government's advisory committee on assisted reproductive technology said two of New Zealand's four fertility providers intended to offer IVM if approved and a third expected to offer it within five years.

Dr Kelly said egg collection was technically more challenging in IVM because the follicles on the ovaries from which the eggs were removed were 5mm or less in diameter, compared with up to 2cm after the IVF hormone treatment.

What is IVM?
IVM (in-vitro maturation) is a variation of the more common IVF (in-vitro fertilisation).

Immature eggs collected from the ovaries, without the usual course of hormone injections to increase the number of mature eggs.

Eggs matured in laboratory for 24 to 48 hours.

Eggs then fertilised, as with IVF, to create embryos, which are placed in the uterus.

Likely to be used by 5 per cent of IVF patients.