Infertility Reasons: Female Age
Studies of pregnancy rates and age support the idea that female fertility declines with age. If you have not considered age as a factor in your infertility, you may be unaware of these pregnancy trends.
- Pregnancy rates begin to decline slowly, beginning in the late 20s.
- Throughout the 30s and early 40s there is an even greater decline in pregnancy rates.
- Few pregnancies are recorded after the age of 45.
- By the age of 30, 7% of couples are subfertile.
- By the age of 40, 33% of couples are subfertile.
Infertility: Why do women lose their fertility as they age?
Egg quantity refers to the number of eggs that you have in your ovaries. At birth, each woman has about 1,000,000 eggs available for fertilization. As you age, the number of eggs in your ovaries begins to decrease. By the time you begin menstruating you have about 400,000 eggs available for fertilization. By the time menopause arrives, most women only have a few hundred eggs left in their ovaries. Because the number of eggs that you have available for fertilization declines with age, this can make it more difficult to become pregnant as you grow older.
Egg quality refers to how ready and able your eggs are to become fertilized. The eggs need to have the right shape, health, and chromosomes in order to be able to develop into an embryo and, eventually, a baby. They also need to be able to combine with sperm in order to produce a child. These characteristics all contribute to your egg quality. Unfortunately, egg quality also changes over time. As you age, your eggs become less able to form a healthy embryo. The chance of fertility problems, miscarriage and fetal abnormalities therefore increase. This is not to say that your eggs are of poor quality just because you’re aging. Many younger women have poor quality eggs while some older women have very high quality eggs. On average however, egg quality does decline with age.
There are many causes of oligoovulation (irregular ovulation) and anovulation (no ovulation) including:
- Ovarian failure (early menopause)
- Polycystic ovarian syndrome, PCOS
- Thyroid dysfunction
- Excessive exercise, stress and anorexia
For natural conception to occur, the sperm must fertilise an egg. This happens in the woman’s Fallopian tubes. Any condition that impedes, or blocks egg transport through the tubes can cause infertility. Pelvic infections (pelvic inflammatory disease), caused by a variety of microorganisms including Chlamydia, can damage the fallopian tubes, as can pelvic surgery or endometriosis. Surgical treatment may be possible but in many cases IVF is the most successful approach.