A few years ago, a West Australian obstetrician and gynaecologist was vilified for suggesting that all women over the age of 35 should not be having babies. As you can imagine, this sparked a wave of criticism and the man was rapidly silenced. Well, without wishing to rekindle an unpopular topic, I thought I would discuss some recent research which looks at the medical aspects of older parents.
Let me start this report by reinforcing the fact that I am making no social comments, criticisms, judgements or suggestions, but purely stating medical fact. As far as I’m concerned, what people do with their own body is their own business as long as it doesn’t involve draining the public purse or harm to themselves or other individuals.
The first obvious fact is that we evolved to the point around 10,000 years ago where our bodies were suited to be Hunter-Gatherers. This involved wandering around a jungle with a spear searching for food in a completely natural environment. But, the reality is that being a hunter-gatherer is not an easy existence, with the average lifespan being somewhere between 30 to 40 years old. Hunter-gatherers met their demise by having their head ripped off by a sabretooth tiger or dying of some serious infection. Thus, the vast majority of hunter-gatherers died soon after the peak of their reproductive career. Typically, young girls would go through puberty in their early teens and soon after become pregnant. Their mothers, in their late 20s or early 30s would help raise the grandchildren in a very simple, “top of the food chain” existence.
Although we haven’t physiologically changed much from 10,000 years ago, the modern world is, of course, so much more complex and obviously (most of the time), so much safer. Rather than squeezing our existence into 30 to 40 years, we are now living double our use-by-date in a much less harsh environment.
One of the obvious consequences of this longer and more complex existence is that teenagers delay the move into adult responsibilities and, for many social, financial, career and lifestyle reasons, many women are now delaying having children until well into their 30s and often in their 40s.
Although this may appear to be the most practical and sensible approach, we still must ask the question, does it have any consequences to the mother or the baby? So, let’s look at the facts. Physiologically, not socially, the ideal time for a woman to have a baby is from age 15 to 25. The eggs are younger, the female body is more supple, with very healthy young breasts to feed the baby. 25 to 35 is still reasonable but over the age of 35 the ability to conceive becomes more difficult and rapidly declines after age 37. The quality and quantity of eggs declines especially after age 30.
Pregnancy risks for the mother & baby
There are much higher rates of hypertension and diabetes as women age, especially if there is concomitant weight gain. Not only can this have a direct effect on the health of the mother but also lead to increased birth defects and potential for miscarriage. Gestational diabetes markedly increases the risk for larger than average babies as well, with all the associated risks.
The three issues of hypertension, diabetes and weight gain also increases the risk for heart disease and stroke. Generally, the older the parents, the higher the risk for all birth defects and miscarriages. It is also a well-known fact that there is a significant increased risk for Down syndrome.
It is a clear and obvious fact that the older you try to conceive, the harder it is and thus it is clearly older women who more typically avail themselves of IVF. A recent study showed a marked increase in heart disease risk over the following 10 years in women who have failed IVF.
A recent study from Iceland has revealed that the age of the parents at conception does influence the amount of mutations found in children. Interestingly, despite the genetic changes being present in the offspring, these changes are not found in the parents. The mutations known as de novo mutations are much more common as the parents age. This study analysed the genomic data of just under 14,700 individuals in Iceland.
The study showed that DNMs (de novo mutations) caused by the mothers increased by 0.37 with each year of age whereas in the fathers this increased by 1.51 per year of age. Thus, older fathers contribute four times more to the problem of these potential mutations creating disease than do older mothers. But, the more severe mutations are influenced by the mother’s age.
From all the information above, it certainly does appear that medically, the West Australian obstetrician/gynaecologist was correct and should not have been vilified. There is no doubt that many people over the age of 35 will conceive healthy, functional children who will contribute significantly to society. But, there is no doubt that the older you are the greater the risks of the pregnancy for the mother and the child. Another issue rarely discussed is that conceiving over the age of 35 means that as a 50 plus year-old, you have to deal with the often annoying behaviour of teenagers. As a father of five, I can tell you this is when it really becomes challenging.