A woman can become a mother at different points in her life, but is there an ideal age? The average age of a first-time mother has risen over time. This is a general trend, but it is particularly noticeable in southern Europe, including of course, Spain.
Pregnancies in women aged over 35 have risen from 5% in the 70s, to 25-30% today. This change has its roots in society and culture. For many working women, a pregnancy can limit career prospects, so the decision to become a mother is postponed for years. Moreover, there is a generalised tendency within society for women to put off having children.
Biologically, the ideal age at which to get pregnant is between 25 and 28, but we can also say that we are programmed to live shorter lives than is the case today. Advances in medicine represent a revolution, opposing laws of ‘natural selection’ — life expectancy has increased, and the standard concepts of ‘youth’ and ‘old age’ have shifted. Therefore for many couples the time to have children extends beyond 35.
However, despite striking improvements in health and in medical care considerably delayed pregnancy has its disadvantages.
The most obvious issue is the reduction in fertility. The average age to reach the menopause has not changed. Both the quality and quantity of eggs reduces over the years, and from the age of 35 onwards, the chances of achieving a spontaneous pregnancy go down. Although many people do manage it, the number of couples needing assisted reproduction is increasing. When pregnancy is achieved, statistically the associated risks are indeed greater, but most women in good health will not notice any significant changes between a pregnancy at 30, and one at the age of 40.
With regard to the foetus, it is true that there is a greater chance of abnormalities or chromosomal anomalies. In the past, 35 was considered the ‘maximum age’ for women wanting to have a child, but this idea has no base in science. There is a progression over time with regard to certain factors: at 25 the risk of having a Down Syndrome child is 1 in 1000, whereas at 40 it rises to 20 in 1000. The probability goes up with age, but even at 40 the real probability is 2%. Moreover today we have a barrage of tests — non invasive tests — for the early detection of abnormalities.
Older mothers are also more likely to suffer complications, such as miscarriage, premature birth, foetal growth retardation — between 1% and 3% — and a slight increase in the occurrence of diabetes or hypertension. Pregnancy is a natural volume overload state, and can accelerate the appearance of these problems, particularly if there is an existing risk of developing such conditions, and this is more likely to be the case at 40 than at 30.
However, as we already know, genetics has almost no influence on health, but the environment — meaning how we take care of ourselves — has a great deal. That is the reason why a woman of 45 with a healthy lifestyle can have a better pregnancy than a woman of 30 with an unhealthy one.
Thus, from the public health perspective, postponing pregnancy is not the best idea, as it increases the need for assisted reproduction and the presence of complications. From a personal point of view, the risks are small, and most women can contemplate pregnancy up to the age of 45 (or beyond) if they are in good health. Another question is whether or not it is good, bad or unimportant that as parents we are 40 years older than our children. But that’s another story…
Eduard Gratacós Solsona, FIVclínic Medical Director