As is the case with all the organs in our bodies, over our lifetime, ovaries go through changes that affect not only their size but also how they perform. The ovaries are situated between the uterus and the fallopian tubes. They are essential to reproduction and, therefore, to the survival of the human race.
The ovaries begin to develop when female embryos are around 8 weeks old and during pregnancy they undergo a number of changes that prepare them for their role in reproduction when a woman is in her childbearing years.
A newborn girl will normally have two ovaries, each one measuring 1 cm in diameter and weighing between 250 and 350 mg. They contain all the cells that will be ovulated later on in life during successive menstrual cycles (400 to 500 ovulations between the ages of 35 and 40 years). This means that the egg that matures, ovulates and travels to the fallopian tubes each month is the same age as the woman herself. New eggs are not generated.
During puberty, and as a result of complex hormonal changes, ovulation takes place for the very first time. The ovaries will have increased progressively in size during infancy and their weight will have increased tenfold. During adulthood, ovaries reach an average size of 3.5 x 2 x 1 cm, equivalent to a volume of between 3 and 6 ml.
Over time, the eggs in the ovaries decrease and ovulations eventually cease. At this point, the woman begins what is known as the menopause. During and following this phase, the ovaries decrease in size until they become similar to when the woman was first conceived.
Is there a link between ovary size and how easy or difficult it is to get pregnant?
We know that ovary size is linked to the number of potential eggs that will be available during a woman’s fertile period. A young woman with small ovaries has a greater chance of having difficulties achieving a normal full-term pregnancy. This is because she will have a lower egg reserve.
Does having large ovaries always mean an increased ability to reproduce?
Having large ovaries does not mean that a woman is more fertile. For example, ovaries can be large in size as a result of cysts or tumours. They are more commonly large in size in women with so-called polycystic ovaries. In such cases, it is frequently linked to an abnormality in ovulation and, therefore, to varying degrees of difficulties getting pregnant.
As mentioned above, size and performance are important and there are simple and accessible tests in order to be able to assess both parameters.
- Ultrasound scans can be used to take quick and easy measurements. They indicate not only ovary size but also something that is, perhaps, even more important: they enable us to count the number of follicles (structures that are visible in ultrasound scan images, the quantity of which is linked to ovarian reserve).
- We can use a simple blood test to determine the levels of hormones linked to ovarian function, including anti-Müllerian hormone, a reliable indicator of the egg reserve in a given ovary.
At Instituto Bernabeu, we have set up a pro-fertility planning unit (Fertyplan) where we evaluate and provide a personalised assessment of a patient’s potential risk of reproductive issues. This enables patients to take decisions on how and when to plan for future pregnancies.