What is low ovarian reserve?
Low ovarian reserve means that the ovaries contain fewer eggs than expected for a person’s age. It refers to the quantity of remaining eggs, not necessarily their ability to be fertilised. Ovarian reserve naturally declines with age, but in some individuals this decline happens earlier or faster than expected.
Low ovarian reserve can make it more difficult to conceive, either naturally or with fertility treatment, because fewer eggs are available for ovulation and fertilisation.
Female ovarian reserve diminishes with age, and consequently, so does a woman’s fertility. From the age of 35, women have about 10 % of their eggs left. This percentage progressively decreases and, between 10 and 15 years before menopause, the decline is accentuated.
Each woman’s ovaries contain about 750 000 eggs at birth, but the range is wide. From puberty, there are about 300 000 eggs left. Each cycle, a woman loses approximately 1,000 eggs as one egg matures into a fertilizable egg. In the middle of the cycle, during ovulation, the mature egg is released as the follicle ruptures. A corpus luteum then forms in place of the ruptured follicle. The rest of the developing follicles disappear. When the next cycle begins, the process repeats itself. Thus, the number of follicles, and the eggs contained within them, decreases cycle by cycle.
Therefore, as menstrual cycles progress, the number of reserve eggs capable of being fertilised and leading to pregnancy gradually decreases. The rate of decline in the ovarian reserve is individual; in addition to genetic factors, it is influenced by lifestyle and certain medical conditions.
A woman’s ovarian age does not correspond exactly to her biological age. There are women of the same age who have different ovarian reserves.
To determine a woman’s ovarian reserve, which refers to the number of follicles (each follicle typically contains one egg and indirectly indicates the number of eggs), a transvaginal ultrasound with an antral follicle count (AFC) is performed during the first days of the cycle. Additionally, anti-Müllerian hormone (AMH) levels are measured, which can be done at any point during the ovarian cycle.
A low AMH result indicates decreased ovarian capacity, but becoming pregnant is possible even if the value is undetectable. A low AMH does not reflect the diminished quality of eggs. The quality is more influenced by age.
If the results of these tests indicate that a woman has a lowovarian reserve, her chances of achieving a pregnancy are lower than with a normal ovarian reserve. Therefore, to fulfil her wish to become a mother, she may opt for the help of an infertility specialist to go through the options. The specific treatment is determined by evaluating other factors, such as the male factor and the age of the patient.
It should be noted that egg quality is a more significant factor than ovarian reserve. Ultrasound cannot detect egg quality; instead, a woman's age provides more information about it. Thus, if a young woman has a low ovarian reserve, she may still have good chances of achieving pregnancy. Conversely, even if a woman over the age of 40 has an excellent ovarian reserve, her fertility is still reduced due to her age.
A fertility specialist will consider your entire fertility picture and help you find the best ways to support you on your path to parenthood.
In Ovumia, we are always ready to help you!
