5–7
The trend for parenthood at an older age has also been seen in men. Since 1980, the GSI-IX fertility rate for men in their 30s has increased by 21%and for men aged ≥ 40 years, the rate has increased nearly 30%. In contrast, the fertility rate in men younger than age 30 years has decreased by 15%.4 The idea that robust fertility for a man will continue well past a woman’s decline in fertility is untrue. Although the female ovarian reserve Inhibitors,research,lifescience,medical is perhaps the most crucial component of a couple’s per cycle fecundity, the age of the male partner also has significant impact on reproduction. Beyond the fact that older men tend to have older female partners, increasing male age is associated with increased time to conception. This reflects the age-related increase in acquired medical conditions, decreases in semen quality, and increasing rates of DNA fragmentation seen in
sperm. In addition, there is an association between age of the male partner and the incidence of birth defects and chromosomal abnormalities. Inhibitors,research,lifescience,medical Age-related infertility will continue to be a problem secondary to women delaying childbearing while obtaining advanced education and establishing a professional career. A basic understanding of these issues is critical for health care currently professionals Inhibitors,research,lifescience,medical so that they can effectively counsel patients who are considering a delay in childbearing for social reasons or for those seeking fertility treatments. The Aging Female Partner Studies that have attempted to assess the impact of male age on fertility have been confounded by the age of the female partner. It is well documented that women have a natural and inevitable decline in fecundity with age. An Inhibitors,research,lifescience,medical interesting example is Tietze’s natural history study of the Hutterite population in North America.8 This sect strictly condemns contraception, and therefore Inhibitors,research,lifescience,medical serves as an ideal population to observe changes in fertility with age. The study showed that 11% of
women were infertile by age 34, 33% by age 40, and 87% by age 45. Further studies have shown that, although there is a mild decrease in fertility in women in their late 20s, a more appreciable deterioration occurs after age 30, and fertility rapidly declines after age 35. In fact, per-cycle fecundity drops from a peak of 25% to 30% per month in the early to mid 20s, to < 5% at age 40. From a physiologic perspective, the greater impact of age on female Cilengitide fertility is understandable. Compared with an average ejaculate that may contain > 40 million sperm, the female fetus has a peak of 6 to 7 million oocytes at approximately 20 weeks of gestation. This number falls through fetal development and at birth there are 1 to 2 million viable oocytes remaining. By the time she reaches puberty, there are only 300,000 to 500,000 oocytes remaining. During the 35 to 40 years of a woman’s reproductive life, she will ovulate 400 to 500 of these oocytes and the rest will be lost to atresia.