Maternal Age and Infertility
The number and quality of oocytes decrease even at an earlier age, but they are clinically displayed at the age of 35. Moreover, the incidence of birth defects and miscarriages increases with maternal age.
The Hutterites are an isolated community living a simple, patriarchal lifestyle which excludes any form of contraception. This community gives us therefore a landmark in terms of natural fertility. The Hutterites have a declining rate in pregnancies simultaneously with increasing age of women, with a 50% decrease of fecundity at age 35.
Another study in a sample of 1000 pregnant women indicates that 71% of the women over 30 years old conceived in an interval of 3 months, while only 41% of the women over 36 years old succeeded in conceiving within the 3 months.
Numerous other studies lead to the same results. One of the main factors which contribute to this decrease is the age chosen for conception. The magnitude of this decline is important both clinically and in terms of social issues.
Despite an impressive amount of data which correlate female fertility decline with age, the risks associated with delaying conception are ignored by the public.
Thus, following a recent study involving students of a university in Sweden, half of the students expressed their intention to have children at the age of 35 years and had no substantial knowledge about fertility decline caused by advanced age .
The effect of age in women who are being treated for infertility is similar to women belonging to the general population area, who display low birth rates along with increasing age. In 2002, in Australia and New Zealand, there were 36,483 MAR treatment cycles. The mean age of these women was 35.2 years, and the mean age of men was 37.6 years. Women between 25-29 years who were under IVF treatment with fresh embryos, and sperm from the partner, obtained a live birth rate of 25.9% , in comparison with rates of 6.1% to women aged 40-44 years.
These data compete with the general population whose fertility peak was observed to be at the age of 22, fertility beginning to decline from 25 and dramatically declining around age 40.
A recent study including all IVF clinics in the Netherlands found that the overall live birth rate decreases by 2% with each additional year of the maternal age.
A Belgian study involving 249 couples under IVF treatment, diagnosed with obstructive and non-obstructive azoospermia, found that high maternal age affect the live birth rate. Women of 20 years old showed a rate of 46% compared with women of 30-36 years old who had a rate of 34%, those who were 37-39 years old had a 13% rate, while those aged over 40 years old had a 4% rate.
Taking into consideration the fact that the live birth rate is the “gold standard” and the success rate in women over 35 decline because of the miscarriages incidence, another study, which involved 201 pregnancies following controlled ovulation stimulation, showed a 2.1% miscarriage in women under 35 and a risk of 16.1% in women over 36 years.
Another study that took into account a number of 821 ICSI cycles performed at a hospital in New York found a significant decrease in pregnancy, implantation and live birth rate per embryo transfer, associated with the increase age of the female partner.
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