Síndrome de ovario poliquístico

Synonym: Stein-Leventhal syndrome

Originally described by Doctors Stein and Leventhal in 1935, the cause of this common, poorly understood syndrome is uncertain, but it is now considered to be primarily metabolic rather than gynaecological. It encompasses a syndrome of polycystic ovaries, in association with systemic symptoms causing reproductive, metabolic and psychological disturbances. These most commonly present with infertility, amenorrhoea, acne or hirsutism.

How common is polycystic ovary syndrome? (Epidemiology) ¹²

Polycystic ovaries on ultrasound are very common and can be seen in up to 33% of women of reproductive age. However, the majority of women with polycystic ovaries do not have features of polycystic ovary syndrome (PCOS) and do not require intervention. Prevalence figures vary depending on diagnostic criteria used, but PCOS is thought to affect 5-15% of women of reproductive age.

Fisiopatología¹

The cause remains unclear but is likely to be multifactorial. The essential changes are:

• Excess androgens produced by the theca cells of the ovaries (due either to hyperinsulinaemia or increased luteinising hormone (LH) levels).

• Insulin resistance, ie loss of sensitivity to insulin, resulting in hyperinsulinaemia in many women with PCOS. Weight gain further increases insulin resistance. Effects of this increase in insulin are:

  • Increased androgen production through more than one mechanism

  • Reduced production of sex hormone-binding globulin (SHBG) in the liver. Free testosterone may subsequently be raised as testosterone is bound to SHBG, even if total testosterone is normal.

• Raised LH levels due to increased production from the anterior pituitary (in around 40% of women with PCOS).

• Raised oestrogen levels in some women, which may lead to a hyperplastic endometrium.

The underlying endocrine disturbance can exist in the absence of polycystic ovaries; affected women may have classical clinical features, yet biochemically normal androgen levels.

The condition appears to have a genetic link in some cases, as there is familial clustering; however, the gene involved and mode of inheritance have not yet been identified.³⁴

Symptoms of polycystic ovary syndrome ⁵

⁶

Symptoms associated with PCOS can occur in adolescence, but it is not considered good practice to make the diagnosis in the first 8 years after the menarche. This is because symptoms such as irregular periods are common in the adolescent population; labelling them as PCOS risks overdiagnosis and unnecessary anxiety. Women with such symptoms should be reassessed 8 years after menarche.

Síntomas

Entre ellas figuran:

• Oligomenorrhoea (defined as <8 periods per year).

• Infertility or subfertility.

• Acné.

• Hirsutismo.

• Alopecia.

• Obesity or difficulty losing weight.

• Psychological symptoms - mood swings, depression, anxiety, poor self-esteem.

• Apnea del sueño.

Clinical signs

Entre ellas figuran:

• The presence of hirsutism, (often on the upper lip, chin, around the nipples and in a line beneath the umbilicus). This occurs in 60% of women with PCOS.

• Male-pattern balding, alopecia.

• Obesity - this is common (usually central distribution).

• Acanthosis nigricans - may be present and is thought to be a sign of insulin resistance.

• Occasionally, clitoromegaly, increased muscle mass, deep voice (more usually, these are signs of more severe hyperandrogenism syndromes).

Criterios de diagnóstico⁷

• Polycystic ovaries (either 12 or more peripheral follicles or increased ovarian volume (greater than 10 cm³) or increased anti-Müllerian hormone.

• Oligo-ovulation or anovulation.

• Clinical and/or biochemical signs of hyperandrogenism.

Differential diagnosis^{1 89}

• Thyroid disorder (particularly hypothyroidism).

• Hyperprolactinaemia.

• Síndrome de Cushing.

• Acromegalia.

• Side-effects of medication (medication causing hirsutism, weight gain or oligomenorrhoea as side-effects, for example).

• Late-onset congenital adrenal hyperplasia (CAH).

• Androgen-secreting ovarian or adrenal tumours.

• Ovarian hyperthecosis.

If there are signs of virilisation, rapidly progressing hirsutism or high total testosterone level then suspect one of the latter three. 17-hydroxyprogesterone, measured in the follicular phase, will be raised in CAH. Consider checking levels even where testosterone is not significantly raised in those with higher risk, such as people with a family history of CAH.

Investigaciones¹⁹

• Total testosterone: normal to slightly raised in PCOS.

• Free testosterone levels may be raised but if total testosterone is >5 nmol/L, exclude androgen-secreting tumours and CAH.

• SHBG: normal or low in PCOS. This can also be used to calculate the free androgen index (= 100 times the total testosterone value divided by the SHBG value). Free androgen index is usually normal or elevated in PCOS and can be used as an alternative to measuring free testosterone if this is not locally available.

• LH may be elevated, with the LH:follicle-stimulating hormone (FSH) ratio increased (>2), with FSH normal; however, this is not part of the diagnostic criteria and may be normal. (Remember the oral contraceptive pill affects levels.) This also helps to exclude premature ovarian insufficiency (LH and FSH both raised) and hypogonadotropic hypogonadism (LH and FSH reduced).

• Ultrasound scan demonstrates characteristic ovaries (the average volume is three times that of normal ovaries); however, the syndrome can exist without the presence of polycystic ovaries. In adolescence a scan should be interpreted with caution as follicle counts are higher.

• Other blood tests, where indicated from the clinical picture, to exclude other potential causes - eg, TFT (thyroid dysfunction), 17-hydroxyprogesterone levels (CAH), prolactin (hyperprolactinaemia), DHEA-S and free androgen index (androgen-secreting tumours), and 24-hour urinary cortisol (Cushing's syndrome).

• Fasting glucose and oral glucose tolerance tests are useful in assessing insulin resistance/diabetes. .

• Assess cardiovascular risk, including lipid levels.

Treatment for polycystic ovary syndrome ¹⁹

See also the separate articles on Acne, Hirsutism, Obesity, Alopecia, and Infertility.

Puntos generales

Women diagnosed with PCOS should be informed of the possible long-term risks to health that are associated with their condition.

Associations with obesity, dyslipidaemia and insulin resistance are likely to result in increased cardiovascular risk. Women should be offered screening for non-diabetic hyperglycaemia and diabetes, and screening for other cardiovascular risk factors. See also the separate Prevention of cardiovascular disease and Prevention of diabetes articles.

Women should also be asked about symptoms of sleep apnoea and informed this is also a risk.

Women diagnosed with PCOS should be advised on weight control and exercise:

• Lifestyle intervention may improve the free androgen index (FAI), weight and BMI in women with PCOS.¹⁰

• Weight loss has been shown to improve fertility, psychological symptoms and metabolic features (insulin resistance and cardiovascular risks), even when BMI remains in the high ranges.¹¹

• Weight loss has also been shown to improve ovulation, pregnancy rates and outcomes.¹²

• A low-GI diet has been shown to improve clinical and biochemical features of PCOS. ¹³

• Hypertension should be treated but there is no use for routine use of statins in women with PCOS, other than normal guidelines for use - evidence in this area is of low quality.⁷¹⁴

Oligomenorrhoea or amenorrhoea may predispose women to endometrial hyperplasia and cancer. Treatment which leads to a withdrawal bleed every three or four months should be recommended with cyclical progestogen or with combined or progestogen only contraception, such as the pill, patch, vaginal ring or implant. Alternatively the levonorgestrel intrauterine device (LNG-IUD) may be used to prevent hyperplasia. Ultrasound of the endometrium should be done if withdrawal bleeds do not occur, and endometrial biopsy is indicated if the endometrial thickness is raised.

Tratamiento farmacológico

There is no treatment which reverses the hormonal disturbances of PCOS and treats all clinical features, so medical management is targeted at individual symptoms and only in association with lifestyle changes.

For women not planning pregnancy

• Combined or progestogen only contraception is also used to control menstrual irregularity. Alternatively, progestogens may be used to induce bleeds to protect the endometrium (eg, medroxyprogesterone 10 mg daily for 7-10 days every three months). Alternatively the LNG-IUD may be used as endometrial protection.

• Metformin:¹⁹¹⁵¹⁶

  • Has been increasingly used off-licence for PCOS; however, the evidence is unclear. The National Institute for Health and Care Excellence (NICE) CKS page on this suggests that we consider seeking specialist advice before initiation, and notes that the benefits may be greatest in those at high metabolic risk.

  • The latest European Society of Human Reproduction and Embryology (ESHRE) guidance on PCOS advises that a shared-decision making approach should be used, considering the following:

    • Metformin generally has the same efficacy as active lifestyle intervention.

    • Use may be associated with low B12 levels, particularly if there are other risk factors such as previous bariatric surgery.

    • Side-effects are usually self-limiting and may be minimised by starting at a low dose or using an extended release preparation.

• Orlistat and GLP-1 agonists can help with weight loss in overweight/obese women with PCOS and may improve testosterone and insulin sensitivity with similar efficacy to metformin.

For women wishing to conceive and presenting with infertility¹²¹⁷
2013 NICE guidelines advise (after weight loss where indicated and a full fertility work-up) that women should be treated with clomifene, metformin or a combination of the two. These decisions would generally be made in secondary care; clomifene in particularly should only be prescribed in secondary care. It should not be used for more than six months. Laparoscopic ovarian drilling or gonadotrophins are second-line treatments for those who are resistant to clomifene.

Complications¹⁷

• Infertility. PCOS is the cause of infertility in 75% of women who are infertile due to anovulation

• Oligomenorrhoea or amenorrhoea are known to predispose to endometrial hyperplasia and endometrial cancer in untreated cases. It is good practice to recommend treatment with progestogens to induce a withdrawal bleed at least every 3 months, unless the woman has a LNG-IUD in place or is using a method of contraception which thins the endometrium.

• Women with PCOS have a higher cardiovascular risk than weight-matched controls, as they have increased cardiovascular risk factors such as obesity, hyperandrogenism, and hyperinsulinaemia, and a higher prevalence of risk factors such as hyperlipidaemia, hypertension, the metabolic syndrome and diabetes. The 2023 ESHRE guidelines recommend that cardiovascular guidelines include PCOS as a risk factor, but this has not yet been done in the QRisk3 tool used in the UK.

• Women diagnosed with PCOS (or their partners) should be asked about snoring and daytime fatigue/somnolence and informed of the possible risk of sleep apnoea. They should be offered investigation and treatment when necessary.

Complications in pregnancy
Women with PCOS have an increased risk of miscarriage, gestational diabetes, hypertension and pre-eclampsia, low birth weight, premature delivery and needing a Caesarean section.