Why it’s better to have children before your 40s

The optimal fertility window for both women (and men) is narrow, and shrinks exponentially with advancing age.

Pregnancies are best planned when fertility rates are highest, couples are in optimal health, and when chances of delivering a healthy baby are highest.

Biologically, the optimal age bracket for the best fertility outcomes spans from the mid-20s to the mid-30s.

This optimal conception decade is dictated by the fact that women are born with a finite, genetically determined number of eggs in their ovaries.

The pool of eggs is highest at birth. However, most of these eggs are destined to die. By puberty, when reproductive capacity is attained, there has already been a considerable decline in egg numbers.

The majority of these remaining eggs are also lost with every menstrual period, leaving limited numbers potentially available for conception between puberty and menopause.

In teenage, the reproductive system is still undergoing the process of physiological (and psychological) maturity. Childbearing at this time is socially undesirable.

However, conception in this age group is fairly commonplace, but with disproportionate pregnancy complications.

The age interval of 25 – 35 years is optimal for childbearing. There are many eggs available, making the chances of conception much higher. The quality of the eggs is better, translating into less risk of miscarriages and birth defects. This is also a period of good general health, and once pregnancy occurs it is more likely to be uncomplicated.

After the age of 35, chances of conception start to decline steeply. The number of available eggs is much lower, and this is compounded by a decline in quality. Ovulation also becomes more irregular. Male fertility mirrors the same decline as in women.

All these factors reduce the chances of conception. By the age of 40, the chances of conception and live birth have declined by about 50 per cent compared to 30 years of age. And no fertility treatment can ever compensate for this biological phenomenon, either in the man or the woman.

Careers and other priorities do not always conform to biological clocks. So what should couples do if they are not ready for a family when it’s biologically optimal? You can always take your chances, and hope that you will conceive when ready.

Fertility preservation options are available, but at great medical intervention and expense. Eggs and sperms can be frozen for future use. Better still, eggs can be fertilised with sperms then frozen as embryos, which have better survival. This gives you a back-up option for the future.

Regardless of age, additional factors can affect your fertility potential. Unhealthy lifestyles, toxins and sexual infections can all decrease your overall fertility. Watch out for these, whilst trying your best to fit into an optimal fertility window.

Dr Alfred Murage is a Consultant Gynaecologist and Fertility Specialist; [email protected]