Not all over-30s will be as lucky as Jacinda Ardern when it comes to babiesby Nicky Pellegrino
After age 30, conceiving naturally becomes more and more of a lottery.
“At 30, there is a 20% per month probability of having a baby,” he says. “People are surprised by that statistic because we’re conditioned through our teens and twenties to trying not to get pregnant. And it declines dramatically. By 40 it’s down to 5% or 6%.”
It is also important for couples to think beyond a first child to the size of family they are aiming for ultimately. “If you’re over 35 and you want three or more children, there’s a less than 50% chance you’ll achieve that with or without IVF [in vitro fertilisation],” says Murray.
The trend towards having children later in life is what lies behind an increased demand for fertility services. And although treatments are being refined all the time, the technology is still limited by the age of the patients. Not only do older women have fewer eggs, but the quality of those that remain may also not be great, with a higher risk of chromosomal abnormalities.
Women are born with a finite number of eggs and recently there was a scare when a review by a team of Dutch scientists found that mice given paracetamol at a critical stage of early pregnancy produced female offspring with fewer eggs. Other animal studies have suggested the commonly used painkiller may disrupt the reproductive system of male babies in the womb.
“This is potentially a cause for concern for women taking a prolonged course of a very high dose in the early stages of pregnancy,” says Murray.
However, paracetamol remains categorised as a safe drug during pregnancy, and taking a couple to treat a headache is extremely unlikely to have any detrimental effect.
“The pragmatic advice is only take medication when you absolutely have to, at the minimum dose for the minimum time.”
Falling sperm counts are also a concern for those trying to conceive – they have dropped by more than half in the past 40 years, according to international research, and are continuing to fall. Murray says Fertility Associates has done studies with sperm donors and seen a significant decrease since the late 1990s.
“No one knows why, but the natural assumption is it’s an environmental influence.”
A recent study looking at a large group of Taiwanese men over a period of two years found that exposure to high levels of air pollution was linked to a higher number of sperm that were abnormal in shape and size. Hormone-disrupting chemicals in everything from pesticides to preservatives and plastics have also been linked to fertility issues, but it’s tricky to prove cause and effect and just as difficult to limit exposure to many of these things in the modern world.
Murray’s advice is to focus on the factors you can control. Weight is one – a high BMI is associated with a lower chance of conception as well as a higher risk of complications during pregnancy. Smoking is linked to miscarriage and infertility. Even coffee can be an issue.
“Caffeine increases the time it takes to conceive,” says Murray.
The equivalent of a can of energy drink or a couple of espressos a day can increase the time by eight months, which is a lot if you’re older. “The advice to women is to minimise intake – for men it seems to make no difference.”
New research from Greece has found that healthy eating is important for women having IVF. Those on a Mediterranean-style diet high in fresh vegetables, fruit, olive oil, fish and legumes have a significantly better chance of becoming pregnant and giving birth.
Murray suggests all women in their late twenties who are still considering having children should take an AMH (anti-Müllerian hormone) test. The simple blood test is the best way to estimate how many eggs are left in your stash. It can also identify women who are likely to go through early menopause.
“We don’t have a test for egg quality; age is the best measure for that.” Ideally, says Murray, couples should do their family and career planning at the same time.
This article was first published in the February 17, 2018 issue of the New Zealand Listener.
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