One of the growing factors is that women postpone starting a family until a later age, they want to be financially secure, travel, build a career.
However, it is true that women are most fertile between the ages of 20 and 25. A woman’s fertility declines over the age of 35 because her oocytes (eggs) are as old as she is. Egg aging is a major factor in infertility.
The eggs of older women more often have genetic abnormalities (chromosomes) and if they are fertilized, the embryo may be damaged (the percentage of children with Down syndrome is, for example: 1 in 2000 women in their 20s, 1 in 900 women in their 30s, 1 in 350 women at age 35, 1 in 110 women at age 40 and 1 in 25 women at age 46).
- ovarian factor
- fallopian tube factor
- immunological factor
- genetic causes
- excessively thick cervical mucus
- congenital developmental womb defects
- idioathic factors
For men, age is much less important. However, an older man has fewer sperm, they are less mobile and may have chromosomal abnormalities. An egg fertilized by such a sperm can be a carrier of genetic diseases or a miscarriage can occur.
- Testicular insufficiency
- Hormonal disease
- Male genital tract obstruction
- Sperm antibodies