A baby girl is born with a genetically determined number of eggs in her ovaries. The unborn baby has the highest number of eggs (7 million) around mid- pregnancy. These are constantly being destroyed such that by birth she has around 12 million eggs. By the time she reaches puberty (adolescence), there are about 400,000 eggs left in her ovaries.
Over the course of her reproductive life, only 400 of these are destined to undergo ovulation (release of egg from the ovary) and the remaining undergoes destruction. This appears like a colossal waste! But scientists explain that this may be nature’sway of allowing only the most robust eggs to be available for reproduction. This process continues until about 1000 eggs are left in the ovaries and this is when the woman reaches menopause. This forms the basis for the concept of the biological clock in women.
Why is it important?
If the number of eggs, to begin with, is smaller than usual or the rate of destruction is faster than usual, the woman can reach menopause faster. When this occurs before the age of 40, it is known as premature menopause. On the other hand, if this mechanism of growth and destruction of eggs becomes abnormal, many eggs get arrested in development, they neither undergo ovulation nor destruction leading, to a condition called PCOS (polycystic ovarian syndrome.) Some situations can cause a faster destruction of eggs such as ovarian cystectomy (a surgery involving removal of cysts from ovaries) or undergoing chemotherapy for cancer.
Does the clock tick faster in Indian women?
It is a known fact that the average age of menopause in Caucasian women is 51 years and that in Indian women is about 47 years. This could mean that Indian women are either born with a smaller number of eggs or these undergo accelerated destruction. A study comparing Indian women with Spanish women showed clearly that being Indian decreased the ovarian reserve such that the number of eggs in the ovaries of Spanish women aged 37 years was the same as that found in Indian women aged 31 years! No wonder then, that when another study looked at the response of women to IVF (in-vitro fertilization,)those from an ethnic minority (Indians, other south-east Asians, Middle-Eastern Asians and Afro-Caribbean) had lesser pregnancies than the Caucasians. Whether this is due to their genetic make-up or environmental factors such as nutrition are something that scientists are still trying to work out.
Changing lifestyles causing double trouble:
With greater emphasis on higher education in today’s age, an increasing number of men and women are postponing having children. This gets further complicated with people working and living abroad. They are either unable to take out time enough to find a life partner or in some situations, they live apart, with the husband earning abroad and visiting the spouse only once or twice a year. The end result is a steady increase in the age of women trying for their first baby.
When this is coupled with the lack of awareness, it results in couples seeking medical advice quite late. Many fertility experts are dismayed by the fact that women often try various religious/ traditional methods to try and become pregnant and by the time they seek medical advice they are close to 40 years or sometimes even more. With increasing age, not only does the ovarian reserve dwindle, but the eggs that are released are also more likely to have defects. Consequently, the pregnancies which result have a higher chance of miscarriage or genetic abnormality. So were our grandmother’s right, after all? Their emphasis on early marriage and early childbearing was based on experience but interestingly science appears to be supporting this viewpoint!
So what can be done?
1. Couples trying for a baby must be aware of the impact of age on ovarian reserve and to a lesser extent on the semen quality too. Work-life balance must take this important aspect into consideration.
2. If a woman is 35 years or more, it’s best to consult a fertility expert if she does not conceive within 6 months of trying.
3. In the absence of a dedicated fertility center, itis reasonable to approach your general practitioner or general gynecologist who can initiate the preliminary tests and simple treatment.
However, if these are not successful, the advice of a fertility expert should be sought straight away so that more elaborate and successful treatments can be undertaken in good time.