"It works for the majority but there's still a lot of people whose fertility declines before they get to that stage so having some accurate information when you're very young, you can think, 'Well, I do really want children, but I'm going to have to go about it in a different order' ... of course you can't escape age no matter how good your fertility."
The average age of menopause is 51 but the ability to conceive falls dramatically 10 to 15 years before menopause.
If a test predicted menopause would start at age 43, for example, the woman's fertility would start fading in her early 20s and be almost gone by her early 30s, markedly altering her family planning choices, Dr Peek said.
Premature menopause, before 40, happened to about one in 100 women and could be genetic or due to environmental factors or conditions.
A person's eggs and sperm are in place by the time a fetus is at 12 weeks' gestation and the mother's health or exposure to environmental factors could condition the baby's reproductive fitness, Dr Peek said.
Smoking can reduce the average age of menopause by two years.
In the research, scientists found complex genetic traits that can determine the age of menopause, which varies among women from 45 to 55.
Fertility Associates' Hamilton medical director, Dr VP Singh, said the test could in future be routinely administered as early as age 18.
Mother says news was a huge shock
Anita Stokes was 29 and about to get married and start a family when she discovered she had already gone through menopause.
A fit and healthy young woman with no family history of premature menopause, Mrs Stokes said she was "absolutely shocked" when doctors told her she could never conceive.
"I was devastated when I found out. I'd been on the [contraceptive] pill for 10 years and I'd gone off the pill and my periods just didn't arrive."
Now 43, Mrs Stokes said doctors could not explain her ovarian failure but pinpointed a battle with meningitis at the age of 20 as a possible factor.
Mrs Stokes, a Waikato primary school teacher, and her husband, Paul, were faced with adoption or using an egg donor if they wanted to pursue having a baby.
They decided to use an egg donor and underwent IVF to conceive fraternal twin boys, who Mrs Stokes gave birth to in July 2002.
She was pleased a genetic test to predict menopause was being developed.
"If only they had that about 12 years ago. Never mind, I got [children] in the end so that's the main thing. It's going to be great for giving people choices."
What is menopause?
• The cessation of menstruation for more than 12 months.
• It happens as the ovaries stop producing eggs.
• The average age is 51.
• Symptoms include hot flushes and night sweats because of the withdrawal of oestrogen.
• Premature menopause can be caused by a family history, environmental factors, auto immune conditions, and chemotherapy.
On the web
fertilityweek.org.nz
nzherald.co.nz
• Read more on pregnancy, childbirth issues: tinyurl.com/nzhfertility
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