Polycystic Ovary Syndrome

What is PCOS?

Polycystic ovary syndrome, or PCOS, is the most common endocrine disorder in women of reproductive age. The syndrome is named after the characteristic small cysts which may form on the ovaries, though it is important to note that this is a feature and not the underlying cause of the disorder. 

The menstrual cycle is a series of natural changes in hormone production and the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive a fertilized egg. These cycles are concurrent and coordinated, normally lasting between 21 and 35 days in adult women, with a median length of 28 days, and continue for about 30–45 years.

Naturally occurring hormones drive the cycles; the cyclical rise and fall of the follicle-stimulating hormone prompt the production and growth of oocytes (immature egg cells). The hormone estrogen stimulates the uterus lining to thicken to accommodate an embryo should fertilization occur. The blood supply of the thickened lining (endometrium) provides nutrients to a successfully implanted embryo. If implantation does not occur, the lining breaks down and blood is released. Triggered by falling progesterone levels, menstruation (a “period”, in common parlance) is the cyclical shedding of the lining and is a sign that pregnancy has not occurred.

In women with PCOS, the natural change in hormonal production is disturbed.

Signs and symptoms

  • Menstrual disorders: PCOS mostly produces oligomenorrhea (fewer than nine menstrual periods in a year) or amenorrhea (no menstrual periods for three or more consecutive months), but other types of menstrual disorders may also occur. 
  • Subfertility: This generally results directly from chronic anovulation (lack of ovulation). 
  • High levels of masculinizing hormones: Known as hyperandrogenism, the most common signs are acne and hirsutism (male pattern of hair growth, such as on the chin or chest), but it may produce hypermenorrhea (heavy and prolonged menstrual periods), androgenic alopecia (increased hair thinning or diffuse hair loss), or other symptoms. Approximately three-quarters of women with PCOS (by the diagnostic criteria of NIH/NICHD 1990) have evidence of hyperandrogenemia
  • Metabolic syndrome: This appears as a tendency towards central obesity and other symptoms associated with insulin resistance, including low energy levels and food cravings. Serum insulin and insulin resistance are higher in women with PCOS. 
  • Polycystic Ovaries: Ovaries might get enlarged and comprise follicles surrounding the eggs. As result, ovaries might fail to function regularly.
  • Women with PCOS tend to have central obesity, but studies are conflicting as to whether visceral and subcutaneous abdominal fat is increased, unchanged, or decreased in women with PCOS relative to reproductively normal women with the same body mass index. In any case, androgens have been found to increase visceral fat deposition in both female animals and women. 


Although 80% of PCOS presents in women with obesity, 20% of women diagnosed with the disease are non-obese or “lean” women. However, obese women that suffer from PCOS have a higher risk of adverse outcomes such as hypertensioninsulin resistancemetabolic syndrome, and endometrial hyperplasia. 

“Lean” women still face the various symptoms of PCOS with the added challenges of getting their symptoms properly addressed and recognized. Lean women often go undiagnosed for years and usually are diagnosed after struggles to conceive. Lean women are likely to have incidences of missed diagnosis of diabetes and cardiovascular diseases. These women also have an increased risk of developing insulin resistance despite not being overweight. Lean women are often taken less seriously with their diagnosis of PCOS and face challenges finding appropriate treatment options. This is because most treatment options are limited to approaches to losing weight and healthy dieting.

It is estimated that 5 to 10% of women have PCOS, making it the most common hormonal abnormality in women.

What are the causes of PCOS?

How PCOS arises is not known. Probably there is not one cause, and several hormones are involved. PCOS occurs in 5 to 10% of all women. In some families, it is more common.

Weight can play an important role in this. Women who are predisposed to PCOS get more symptoms of PCOS as they get fatter. Because being overweight is more common nowadays, PCOS may also be expressed more often.

What are the risks of PCOS?


Excess weight is often accompanied by a reduced sensitivity to insulin, which the body produces. To keep the glucose level at a normal level, more insulin is produced. A continuously high insulin production disrupts your metabolism so that you can eventually get diabetes.

High blood pressure, elevated cholesterol, and cardiovascular disease

Being overweight, high testosterone levels and diabetes give an increased risk of high blood pressure, increased cholesterol levels, and cardiovascular disease. Preventing or treating these problems through weight loss, diet, more exercise and, if necessary, the medication reduces the risk of damage to your body.

Endometrial cancer

Under the influence of estrogen, the mucous membrane in the uterus thickens. Because there is no ovulation, no progesterone is produced, and the mucous membrane is not rejected. If this process continues for years, it is more likely that growths will form in this tissue and there is an increased risk of uterine cancer. This risk can be remedied with progesterone. This can be done by inducing a period 3 to 4 times a year with medications containing progesterone. Another possibility is the pill or a Mirena spiral that also contains progesterone. As a result, the mucous membrane of the uterus remains thin.

How does a menstrual cycle work?

If you want to understand what happens with PCOS and why which medications can work, it helps if you look into the normal menstrual cycle. You can find more information about the normal menstrual cycle on Freya’s website (Your menstrual cycle).

The menstrual cycle is a complicated interplay between different organs in the body: the hypothalamus, the pituitary gland, the ovaries, and the uterus. The hypothalamus is located at the bottom of the brain, just below it is the pituitary gland (brain appendage). The hypothalamus is the ‘big regulator’ on the whole. This produces LHRH, a messenger hormone, which stimulates the pituitary gland to release FSH and LH. FSH and LH are transported through the blood to the ovaries and are responsible for egg maturation and ovulation. FSH stimulates the growth of a follicle (eiblaasje) in which an egg cell is located and ensures the production of estrogen in the ovaries. The estrogen causes the endometrium to grow. If the amount of estrogen in the blood is high, the release of FSH is inhibited and the release of LH is stimulated. Under the influence of that large amount of LH (LH peak), ovulation occurs in the middle of the cycle. The ovaries will now make progesterone in addition to estrogen. This hormone ensures that the endometrium contains enough nutrients for the possibly fertilized egg. If the egg is not fertilized, the amount of estrogen and progesterone in the blood drops significantly. The consequences of this decrease are the rejection of the endometrium and bleeding (menstruation). In addition, the low estrogen concentration in the blood causes the pituitary gland to be stimulated again by the hypothalamus to release FSH and LH. The next cycle has then begun. 


The primary treatments for PCOS include lifestyle changes and the use of medications. 


Goals of treatment in the case of PCOS may be considered under four categories:

In each of these areas, there is considerable debate as to the optimal treatment. One of the major reasons for this is the lack of large-scale clinical trials comparing different treatments. Smaller trials tend to be less reliable and hence may produce conflicting results. General interventions that help to reduce weight or insulin resistance can be beneficial for all these aims because they address what is believed to be the underlying cause but not for ‘lean’ women. As PCOS appears to cause significant emotional distress, appropriate support may be useful. It is important to address this topic at Gynaecologie Amsterdam.

What treatment is possible for PCOS?

First, your doctor at Gynaecologie Amsterdam needs to know if you want to become pregnant.

If you don’t want to get pregnant

If you do not (yet) want to have children or if you stop the hormone treatments or if you have given birth, the advice is to use the pill or a Mirena spiral. Due to the progesterone in these agents, the mucous membrane of the uterus remains thin. This way you prevent an increased risk of uterine cancer. Another way to solve this is to induce bleeding once every 3 to 4 months with a medication that contains progesterone.

If you are overweight, a healthy lifestyle is important to prevent the risks associated with obesity. If you suffer from acne or excess hair, the pill is recommended. The pill reduces the effect of the male hormone. Excess hair does not disappear, but new hair formation is prevented.

If you do want to get pregnant

Weight loss

If you are overweight, a healthy lifestyle is important. Both for the future and your pregnancy wish. Losing weight is then the first choice of treatment. For some women, the cycle starts again when they start losing weight. Sometimes you still need medication. This medication works better after weight loss or lifestyle improvement. Both the chance of spontaneous pregnancy and pregnancy after fertility treatments are increased as a result.

Ovulation induction by Letrozole

At Gynaecologie Amsterdam you will be treated with Letrozole. By taking tablets from cycle day 3 to 7, ovulation is induced in most cases. Letrozole is an antioestrogen. Through a 2.5 mg of Letrozole tablet, the brain receives the signal that too little estrogen is being made. The pituitary gland responds by making more FSH. This can be just enough to allow one egg to mature further and come to ovulation. If 2.5 mg is not enough to ovulate, the dose can be increased to a maximum of 3 tablets of 2.5 mg.

About 80% of women ovulate and about 50% of women become pregnant with this treatment. Because Letrozole slightly over-stimulates the ovaries, there is an increased risk of multiple pregnancies. Starting this treatment ultrasounds are made to check follicle growth and blood tests are done one week after the ovulation to be sure ovulation had taken place and the treatment is successful. 

Injections: FSH (various brands)

If Letrozole does not work, then injections of a follicle-stimulating hormone (FSH) are the next step. Daily injections of FSH induce egg cell growth. We will not treat you at Gynaecologie Amsterdam but will refer you to the hospital. 


LEO stands for laparoscopic electrocoagulation of the ovaries. Through keyhole surgery, several small follicles on the edge of the ovaries are burned away through superficial small holes. A beneficial effect of this damage is that very often a cycle of its own temporarily arises. Also, after the treatment, the person is often better and easier to stimulate with hormone preparations. The disadvantages are that the result cannot be predicted and is only temporary.

The chance of pregnancy, and multiple pregnancies, is lower than treatment with hormones. For this treatment, we’ll refer you to the hospital. 

We are happy to answer your questions or if you have any suggestions, please let us know at info@gynaecologieamsterdam.nl

Furthermore, download this app https://www.askpcos.org/