Prevalence
Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age Citation[1]. The syndrome was first reported by Stein and Leventhal in 1935 Citation[2]. Since then it has attracted attention owing to its genetic heterogeneity and diverse clinical manifestations.
For over 70 years, there was no consensus on almost all the aspects of PCOS. The incidence of PCOS was reported to be 4–10% of women of reproductive age Citation[3]. However, studies based on ultrasound examination in the general female population of fertile age showed an incidence of polycystic ovaries of 22% Citation[4]. In other studies, the prevalence varied from 5% in the USA Citation[3] to as high as 33% in the UK Citation[5].
Polycystic ovaries were found to be a common finding in the general population as diagnosed by ultrasound in 23% of a group of volunteers who considered themselves ‘normal’ women Citation[6]. On the other hand, of 12,160 laparotomies conducted in women in reproductive age, polycystic ovaries were reported only in 1.4% Citation[7].
Pathogenesis
There is increasing evidence to support a major genetic basis for PCOS Citation[8]. Familial clustering of PCOS has been consistently reported, suggesting that genetic factors may play a role in the development of the syndrome. Numerous genetic mechanisms have been proposed Citation[1]. However, cytogenetic studies failed to demonstrate a specific gene disorder in PCOS, while specific gene analysis showed different altered patterns of expression suggesting a genetic origin Citation[9], and it was concluded that PCOS is a complex and heterogeneous disorder, presenting a challenge for investigators. Currently, PCOS is considered a polygenic trait that might result from the interaction of susceptible and protective genomic variants under the influence of environmental factors.
Diagnostic criteria of PCOS
The diagnosis of PCOS was first described by Stein and Leventhal in 1935 as a combination of amenorrhea or oligomenorrhea, hirsutism, obesity and polycystic ovaries as diagnosed by laparotomy at that time Citation[2]. Nearly 30 years have passed since the first international conference on PCOS was held at the NIH. During these years, it was realized that polycystic ovaries is purely a description of ovarian morphology while PCOS is a syndrome. Tens of definitions and variable combinations of manifestation represented PCOS by different clinicians.
Following the 1990 NIH meeting, the diagnosis of PCOS was based on a combination of oligomenorrhea or amenorrhea and clinical evidence of hyperandrogenism in the form of acne and hirsutism. It was also based on absence of adrenal thyroid or prolactin abnormalities. Ultrasound appearance of the ovaries was not included Citation[10].
A revised Rotterdam Consensus on the diagnostic criteria of PCOS was published in 2004 Citation[11]. The diagnosis of PCOS is based on three criteria: oligo- and/or an-ovulation; clinical and chemical signs of hyperandrogenism; and ultrasound diagnosis of polycystic ovaries. Two of these three items are enough to diagnose PCOS after exclusion of other etiologies for hyperandrogenism.
Ultrasound criteria for polycystic ovaries were the presence of 12 or more follicles in each ovary measuring 2–9 mm and/or an increased ovarian volume of more than 10 ml.
In spite of the big effort of the NIH, the European Society of Human Reproduction and Embryology, and the American Society for Reproductive Medicine to have uniform diagnostic criteria for PCOS, we are far from a perfect consensus.
Treatment of PCOS
There is a general consensus that change in lifestyle, mainly by losing weight, will improve menstrual regularity and chances of pregnancy Citation[12]. However, nearly half of women with PCOS are not obese Citation[13], thus they will not benefit from weight loss.
Use of metformin in PCOS patients
Metformin has been used extensively in the treatment of women with PCOS for improving ovulation Citation[14]. However, two large randomized studies have shown that metformin alone or in combination with clomiphene citrate will not improve ovulation and pregnancy rates Citation[15,16].
On the other hand, a meta-analysis of the use of metformin in ovulation induction for PCOS patients that included 17 randomized studies concluded that metformin alone increases the likelihood of ovulation, and in combination with clomiphene increases the odds of both ovulation and pregnancy Citation[17].
It appears from the available data that there is no consensus on the use of metformin for ovulatory dysfunction in PCOS patients.
Ovarian surgery for treatment of PCOS
The original operation of ovarian wedge resection via laparotomy was abandoned because of the high risk of peritubal adhesions Citation[2]. Ovarian laparoscopic cauterization was used to replace open surgery Citation[18].
A Cochrane review comparing laparoscopic ovarian cautery versus ovulation induction by FSH showed similar ongoing pregnancy rate Citation[19]. However, it is not clear how much thermal energy is required for laparoscopic ovarian drilling, or the number of punctures Citation[20], or whether to cauterize one or both ovaries Citation[21].
Conclusion
In conclusion, clinicians and scientists have worked very hard for several decades to define the syndrome and determine the underlying pathogenesis, the optimum criteria for its diagnosis, and the best available treatment. However, the complexity of the syndrome has made it difficult to have a universal acceptance of all aspects of PCOS.
Financial & competing interests disclosure
The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.
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