Age matters
Is there an ideal age to have kids? If so, what is it?
Some people say the best age to have a baby is when you are physically, mentally
and financially ready, but is there a time when you're all of these things at once?
You may be at your physical peak in your twenties, but mentally you may be 10 or
more years away from starting a family. Financially, you may not be secure until
you reach retirement age! So is it possible for there to be an ideal age to have
a baby?
THE WAY WE WERE
Since you were born there's been a major shift in the age that women are having
their babies. In 1971 the median age of mothers giving birth was 25 years, according
to the Australian Bureau of Statistics. By 2001 the median age had jumped five years
to 30 years of age. During this time, women aged 30-34 years had the highest fertility
of all age groups, while the fertility of women aged 20-24 years continued to decline.
In 1982, women in this younger group accounted for 104 babies per 1000 women but
by 2002 it had almost halved to only 56 babies per 1000 women.
It's believed these changes in childbearing age reflect women's greater control
over their fertility, and a tendency for women to delay having babies due to more
education and employment opportunities. And it's not just women making these decisions,
says Dr Dianne Rudd, senior lecturer at Adelaide University.
"Boys aren't necessarily flocking to do it early either, and parents don't
expect their child to leave home and get married at a younger age," Dr Rudd
says.
Another contributing factor is the assumption you can delay having a baby because
if you run into fertility problems later you can fall back on IVF, says Dr Kelton
Tremellen, deputy medical director at IVF clinic Repromed.
"Some very prominent women, such as Hollywood stars, have had babies at the
age of 47 with the aid of IVF. The reality is they're using donor eggs from younger
women and are having those eggs impregnated by IVF. It creates a false expectation
that people think they can fall back on IVF," he says.
BIOLOGICAL CLOCKS
For women, fertility remains fairly static until the age of 30 but then it starts
to decrease.
"By the time a woman reaches 35, it takes her twice as long to conceive as
a women who is 30 or younger, and by the time she reaches 40, it takes her four
times as long as a woman who is 30 or younger," says Dr Tremellen. "It's
a rapid drop off. The average couple under 30 will conceive in around three to four
months. When you get to 40, it's more like nine or more months."
You probably know women who've had successful pregnancies and healthy babies in
their forties. While it is possible, it's worth knowing that these women are at
a higher risk of complications than younger women. They're more likely to get diabetes
and have high blood pressure, which can result in conditions such as pre-eclampsia,
premature delivery, placental problems and even some birth defects.
The risk of having a baby with chromosome abnormalities, such as Down syndrome,
is significantly higher in older women compared to younger women, too.
The miscarriage rate increases with age, as well. While the figures seem to vary,
some reports say it goes from about one in seven for women younger than 25 to as
high as one in two for women in their mid-forties. Additionally, if older women
do have fertility problems there's less time to seek effective treatment.
"In our experience in IVF, trying to conceive beyond the age of 44 is almost
impossible," says Dr Tremellen. "Women don't have as many eggs left but
the egg quality is also a problem.
"A common misconception is that if you don't fall pregnant before age 44 you
just turn up for IVF and they give you drugs and that will fix the problem.
"However the quality of the eggs we get out are predetermined by the woman's
age, and drugs can't change that. Eggs we get from a 44-year-old are 44-year-old
eggs. They don't work that well, and the genetic abnormality rate is high and miscarriage
is high."
Most worryingly, he says 10% of women have premature ageing of their ovaries, so
they're critically running out of eggs by 35.
WHAT ABOUT MEN?
While the outlook isn't great for women who let their biological clocks tick too
long, Dr Tremellen warns that men also shouldn't think they can delay having a baby
without seeing consequences.
"It's not as dramatic for men as for women - there are blokes in their nineties
who can conceive. But studies show a slow decline in sperm count and swimming activity
with time," he says.
"What's really worrying is that as a man gets older the amount of DNA damage
in his sperm increases. There's now been a link between that DNA damage and illness
in children. For example, dwarfism (or achondroplasia) is more common if the father
is older. That's because the gene in that condition gets mutated as you get older.
Other studies have found that the older the father is, the higher the chance of
his child having schizophrenia. So it's not entirely true that men are ready to
roar right up until they die."
The ideal age for men to start having babies is before 30. Studies have shown that
the older the man gets, the longer it takes to conceive, even if his partner is
young.
"A US study found that as a man gets older the free radical damage in his sperm
increases, and in turn causes DNA damage which can cause infertility," Dr Tremellen
says.
MUMS OF THE FUTURE
So with so many of us delaying parenthood, it would seem fertility problems are
going to be more common in the future. It's a problem the Fertility Society of Australia
is trying to tackle. In 2006, they performed two national surveys that revealed
alarming misconceptions about fertility in both the community and among healthcare
providers. As a result, they believe there's an urgent need to provide clear, consistent
messages about fertility and how to preserve it, both to healthcare professionals
and Australian men and women on a national level.
While it makes sense for health professionals to be encouraging women to have their
babies at a younger age, the message isn't always received well.
"I've said things like this in the past but have been howled down as a caveman
who's trying to keep women barefoot and pregnant in the kitchen," says Dr Tremellen.
"I tell them they'll always have the opportunity to advance their careers but
they won't always have the opportunity to have children."
However, the fact is it isn't always possible for a woman to have a baby before
she's 30. She may be just starting a career, paying off huge university debts, or
hasn't met the right man yet.
In this case, Dr Tremellen believes there is a need for technological advances where
women can freeze eggs, or at least have a liberalisation around the laws concerning
donor eggs.
"At the moment you can't pay egg donors but in the US you can, and they have
no shortage of egg donors. I understand there are ethical issues and problems with
coercion and people regretting it later on in life, but it certainly deserves consideration,"
he says.
With these advances in technology, it would become increasingly possible for much
older women to give birth, even beyond menopause (usually around 51).
"The uterus doesn't really age," says Dr Tremellen. "Fibroids are
more common with age and, if they're large, they can affect the attachment of the
embryo. But in general there's nothing wrong with the uterus even past menopause
if you're given the right hormones."
So will we see women aged 70 becoming mothers in the future? Dr Tremellen says it's
unlikely. "You have to ask, 'Is it in the best interests of the child?' Here
in Australia you wouldn't treat women beyond the age of menopause. In fact, legally
you are not allowed to because it's not in the best interest of the child,"
he explains.
"If you put eggs into a 60- or 70-year-old woman, who's looking after that
child when the mother dies in 10 years?"