A woman is born with all the reproductive eggs she is supposed to have in her lifetime. As a woman ages, the number of these eggs starts decreasing. This is contrary to the sperms produced in men, in whom the reproductive cells are being continuously produced once they reach puberty. Hence, the difficulty in conceiving as a woman becomes older. Also, the eggs start 'aging' over time. Therefore, as a woman becomes older, the eggs in her have greater chances of having defects. The result is an increase in the probability of genetic abnormalities, like, Down's syndrome in children of older mothers as well as miscarriages.
Besides the facts concerning the number and quality of eggs present in a woman, other factors that influence fertility are:
- Hormonal changes
- Thinning of the lining of the womb, that becomes hostile to a fertilized egg
- Irregular menstrual cycle
- Diseases of the reproductive system, like, endometriosis, polycystic ovarian syndrome (PCOS), and chlamydia.
There are various causes of infertility in women. However, age is the single most important factor that affects a woman's reproductive capabilities. What is interesting is that, most of the reasons for decreasing pregnancy rates are dependent on the age of a woman. Fertility in women starts decreasing roughly from the 27th year onwards. However, the effects of the changes on the reproductive abilities of a woman, as she grows in years, become glaringly evident once she crosses the age of 40. For example, a woman in her 20s has a 20 to 30% chance of getting pregnant in every cycle. Chances of a miscarriage are 5 to 10%, and the probability that her baby would have genetic defects like Down's syndrome is 1/1200. In women in early 30s, fertility falls to 15%, and the rate of miscarriage increases to 20%. In case a woman in this age does not conceive after actively trying for 9 months, she should seek medical help. At the age of 35 to 40, the rate at which a woman can conceive falls to 10%. The miscarriage rate increases to 25%, and the probability of having genetic defects in the fetus increases to 1/350. Most healthcare professionals advise women over 35, to undergo genetic testing to find out genetic abnormalities.
After a woman reaches 40, her fertility rate drops to 5%. The rate of miscarriage increases to 33%, and the possibility of genetic abnormalities in a child increases to 1/38. Studies reveal that 90% of the eggs in women above 40 have genetic defects. Also, the pregnancy rate through in vitro fertilization (IVF), which is the most successful infertility treatment, is only 10% in these women. Hence, they must seek professional help, if they do not conceive after having actively tried for 3 months.
Once a woman crosses 45, egg donation becomes the only option for getting pregnant. Pregnancy rate for women over 45 is only 1%. This is because, after this age, all the eggs in a woman are genetically inviable. Even in case of egg donation, the age of the egg donor is important. Even if the egg donor is young, in case the woman has crossed 45, an important question to consider before she tries to conceive is, whether her body would be able to bear the stress of pregnancy. Although, with scientific developments, in vitro fertilization has become the answer to infertility problems, this technique has its own drawbacks that are often overlooked. Some of the complications of IVF are premature birth and disabilities in babies.
Scientific advancements have perhaps blinded us to the fact that age does have an effect on a woman's reproductive performance. With the increasing trend of postponing pregnancy, infertility in women is emerging as an alarming fact.