The Facts: Women, Age and Fertility

AGE RELATED INFERTILITY(ARI) Part 1

Scientific evidence shows that in women, fertility peaks in mid 20s and starts a steep decline in mid 30s despite this so many people still postpone starting a family. Some modern women want to focus on education, build their career, and of course some want stable financial base, or the “right man” may not be coming, so the need to wait for ‘’the perfect partner’’. Whatever the reasons for delaying parenthood are, it is however unfortunate that the natural clock doesn’t stop ticking hence the human body keeps aging inevitably. It is a fact that in today’s society, inability to conceive due to age is becoming much more common because women are waiting until their 30’s and 40’s to have children. Although many women are healthier in later life and taking better care of themselves, this does not stop the natural age-related decline in fertility. Recent reports from the European Society of Human Reproduction and Embryology (ESHRE) have shown that more women are delaying childbearing at the present time than previously. This trend is expected to cause a corresponding rise in the mean age at which women first present with infertility and this brings usto the discussion for this week: AGE RELATED INFERTILITY as it affects both males and females.

WHAT IS AGE RELATED INFERTILITY:  This is the decline in fertility that comes with age, seen in bothmen and women. It is a known fact that age related Infertility affects both sexes, its effect is however seen much earlier in women than in men.  Women 30 years and above have reduced quantity and quality of eggs in their ovaries while male fertility starts to decline after 40 years when sperm quality begins to decrease. All these automatically increase the risk for chromosomal abnormalities like having too many or too few chromosomes (aneuploidy) which might result in conditions such as, implantation failure, Down syndrome and even higher chances of miscarriages.  Older women are also more likely to have health problems that may interfere with fertility making pregnancy and delivery of a live birth more difficult.

The Facts: Women, Age and Fertility

Women in their 20s have a 20-25% chance of achieving pregnancy during their ovulation period. This drops to 15-20% for women between the ages of 31 years  and 35 years and to less than 10% for women ages 35 years and older. By 40 years women typically only have a 5% and by 45-49 years a 1% chance of becoming pregnant without fertility treatment per month.

Women are born with all the eggs they will ever have, unlike men who typically make new sperm throughout their life. Each month many eggs begin to develop, only one or two reaches maturation and eventually ovulates (releases), the others undergo a process called atresia (degeneration). This process occurs in intrauterine life (before birth), before puberty, and during a woman’s reproductive years, even while pregnant or on oral contraceptive.

This progressive loss of eggs over a lifespan results in low egg numbers (quantity) that result in lower pregnancy rate beginning usually in the 40’s. There is also a corresponding loss in the quality of the eggs over time. As eggs age, they become less able to fertilize or even implant normally and are more likely to result in a pregnancy that miscarries.

In addition, for a variety of reasons the process is accelerated in some women whose egg quantity and quality is low at a much younger age e.g. those diagnosed with Premature Ovarian Insufficiency (POI).

Although the average age of menopause (no remaining egg) is about 51 years. The decrease in the ability to conceive due to low egg quality and quantity occurs long before, usually beginning in the 30’s and becoming more pronounced in the early 40’s. Womenin their late 40’s rarely have a spontaneous pregnancy and if so, one in three will miscarry. It is due to this sense of urgency that women 35 years and above should consider visiting fertility experts for evaluation and have their fertility profiling done as soon as they suspect difficulty becoming pregnant.

If a woman’s egg quality or egg number is lower than expected for her age, there may be a discoverable treatable cause.

Are there other factors that can decrease ovarian function in women apart from age such as Endometriosis, Severe pelvic adhesion, Previous chemotherapy or radiation, history of smoking, ovarian surgery or removal of a portion or all of an ovary or both, genetics (Turners syndrome) etc.

However, decreased ovarian function can also occur in women without these predisposing factors. The cause of an early loss of eggs in some women is sometimes not clear, but it is thought to be due to genetic factors with or without a family history of early menopause.

The rule of 3’s- if a healthy woman irrespective of age, has conceived and made it up the first trimester, her odds of the pregnancy resulting in a live birth are almost the same regardless of age. The chances of having a good outcome and a healthy baby are very high. Of course all routine testing are still recommended during prenatal care.

It is worthy of note that the process of egg loss happens at a predictable and steady rate even if a woman takes good care of her health and looks young physically. Both egg quantity and quality determines a woman’s ability to conceive and both are influenced by age and it is important to note that pregnancy is often possible with the right combination of treatment by fertility specialists.

… To be continued.