Age and fertility.
What is ovarian reserve?
Every woman is born with limited number of ova. It can be assumed that, on average, she has about 400 000 of them. As she grows older, she gradually loses them, so that female fertility declines. The number of ova that remain is referred to as the ovarian reserve.
The pool of egg cells starts to decline from around the age of 20. For the next 10 years, this process is quite slow, but after the age of 25 it clearly accelerates. By the age of 30, women have around 100,000 eggs left, which means that the chances of pregnancy decrease from 40 per cent to 30 per cent. A 40-year-old woman has 35,000 of them and only a 15 per cent chance of becoming pregnant. The rate at which the ovarian reserve decreases is very individual. At the same time, it is worth remembering that it is completely unrelated to the outward signs of ageing.
When the ovarian reserve is exhausted and the ovaries stop working, a woman enters the menopause. This usually occurs between the ages of 45 and 55. Menopause cancels out the chance of a natural pregnancy. Unfortunately, however, there are cases where much younger women, even teenagers, enter menopause.
What is premature menopause?
Premature cessation of ovarian function can occur due to genetics, disease or medical procedures. Premenopause refers to menopause before the age of 40.
Premature as well as natural menopause can be spotted by the following symptoms:
- irregular or increasingly infrequent periods,
- Menstrual periods that are heavier or lighter than usual,
- hot flashes (a sudden sensation of heat that spreads throughout the upper body),
- vaginal dryness,
- urinary incontinence,
- Irritability, mood swings, mild depression,
- dryness of the skin, eyes or mouth,
- weight gain,
- concentration problems,
- insomnia,
- reduced sex drive.
The first three of these symptoms are a sign that the ovaries are producing less oestrogen. If you notice symptoms of premature menopause, it is worthwhile to go for tests. The most important test used for diagnosis is a blood test that measures levels of follicle-stimulating hormone (FSH). FSH causes the ovaries to produce oestrogen. When the ovaries slow down the production of oestrogen, FSH levels rise. An index above 40 mIU/mL usually means that the patient is in menopause.
What else affects the reduction of ovarian reserve?
Ageing naturally reduces the pool of egg cells. However, it is not only age that affects female fertility. Other causes of reduced ovarian reserve include surgical procedures on the ovaries, such as removal of cysts, tumours or endometriosis. Some women have a low reserve that is genetically determined. Other factors that can cause premature menopause include:
- chemotherapy and radiotherapy,
- chromosomal abnormalities (X chromosome abnormalities),
- autoimmune diseases (e.g. Hashimoto's disease).
Of the factors for which a woman is responsible, cigarette smoking is the most significant. Environmental factors such as air pollution or contact with harmful chemicals and detergents are also suspected of having a negative effect on fertility. Eating processed foods and using cosmetics with harmful ingredients can have a similar effect. It is advisable to look after your health at every level and choose healthy food products and natural, proven cosmetics.
Ovarian reserve test
Ovarian reserve is checked by testing the level of AMH (Anti-Müllerian Hormone) in the blood. The AMH test can be performed at any phase of the cycle, as the amount of hormone remains constant throughout. At AMH hormone levels hormone or contraceptive therapy also has no influence. Very low levels of this hormone are an indication for in vitro fertilisation.
Female age and egg quality
A woman's fertility also depends on the quality of the eggs that are in her ovaries. A woman's age is crucial in this regard. The ability of women in their 36s to have children is half that of women in their 20s. When a woman exceeds 37 years of age, the reduced quality of the eggs often contributes to the difficulty of getting pregnant. In addition, the incidence of genetic defects in the egg cells increases with age. For this reason, pregnancies at a late age have a higher risk of miscarriage or of giving birth to a child with a genetic disease.
How does age affect male fertility?
Men remain fertile until old age. However, the number of semen abnormalities increases with age. After the age of 40, and particularly after 45, there is a decline in semen quality, which is very often the cause of failure when trying to have a child.
When putting off parenthood, it is worth being aware that the later you decide to try for a baby, the lower the chances of pregnancy. Therefore, when a woman decides to being a mum after the age of 35, she and her partner should attend the examination together.
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