The ovaries

The two walnut-sized organs sitting on either side of the uterus are the hormone and egg-producing powerhouses keeping your reproductive system going.

Whether you’re pursuing motherhood or resolutely avoiding it, your ovaries are producing oestrogen and progesterone to regulate your menstrual cycle and provide your womanly figure. Your ovaries also produce the testosterone your body needs for a healthy sex drive. Every month during ovulation, either the right or left ovary produces a single mature egg to be fertilised (non-identical twins are a different matter!)

When you’re born, your ovaries contain around 1 million ovarian follicles, each with a hollow ball of cells and an immature egg.

As you grow up, about half of these follicles are absorbed by the body, and once your menstrual cycle begins, you’ll have about 400,000 left to play with. Although only one egg usually fully matures during ovulation, between 10 and 20 follicles begin the process of maturation monthly and are reabsorbed before ovulation occurs—like a race to mature first. The ovaries even grow during ovulation as the follicles mature but this is only temporary—once you’re through the menopause and your ovaries retire, they’ll literally shrivel up.

The oestrogen produced by the ovaries fluctuates over the menstrual cycle, and ovulation starts when oestrogen drops. The pituitary gland then increases its secretion of follicle-stimulating hormone, which prompts the follicles to begin maturing. Once the matured egg has eased towards the surface of the ovary, the follicle and the ovarian surface open up to allow the egg to drift out. Progesterone production steps up to thicken the uterine lining while the egg makes its way through the oviducts and fallopian tubes into the uterus. It can take three to five days for the egg to reach the womb and, if unfertilised, it joins the uterine lining as it sheds via monthly period. At the end of the period, the whole process then starts over again.

The ovaries are susceptible to various issues, including low body weight. When women lose too much weight or female athletes aim for a body fat percentage that is too low, the ovaries can cease to work and stop producing the hormones and eggs. Once you gain some weight back, the ovaries should begin to function again. They can also be susceptible to cancer, with ovarian cancer often called the ‘silent killer’. It can be one of the hardest to detect as symptoms are very commonplace, including bloating and abdominal pain. Luckily, if it’s found early, ovarian cancer is treatable. Ovarian cysts are the most common complaint with ovaries; fluid-filled pockets which occur when the egg is not properly released or the follicle does not dissolve properly. Most are harmless, and will go away on their own, but they can cause trouble if they bleed, twist or rupture. The most common hormonal disorder among women, polycystic ovary syndrome develops when numerous cysts remain on the ovaries. The cysts themselves are not harmful, but the hormone imbalances they may cause can lead to serious health problems. ■