- 10 Min
PCOS is the commonest endocrine metabolic disorder affecting 6 - 10% of women in the reproductive age group and is a commonest cause for infertility in this age group. It is associated with obesity, dyslipidemia, Insulin resistance, type II diabetes mellitus and metabolic syndrome.
The features of PCOS include
a) Clinical & / or biochemical hyperandrogenism (HA)
b) Ovulatory dysfunction (OD)
c) Polycystic ovarian morphology (PCOM).
Women with PCOS do not have a homogenous presentation and they are classified into phenotypes
1. Phenotype - A (HA +OD + PCOM)
2. Phenotype - B (HA + OD)
3. Phenotype - C (HA + PCOM)
4. Phenotype - D (OD +PCOM)
Prevalence: Phenotype - A is the most common among the clinical population where as phenotype - C among the unselected population. The prevalence of these phenotypes are A - 67.7%, B - 11%, C - 17.7% and D - 3.6%.
This includes phenotype A and B. They are more hirsute, obese with irregular cycles and more likely to have insulin resistance, dyslipidemia, and hepatic steatosis with increased risk of metabolic syndrome than phenotype C and D.
PCOS women with phenotype - A have significantly higher BMI, clinical and biochemical HA, menstrual irregularities, ovarian reserve parameters, fasting insulin, HOMA -IR and deranged lipid profile. They also had higher 17 - OH progesterone, LH and LH: FSH ratio. These women also are at risk of adverse metabolic and cardiovascular outcomes.
This includes phenotype - C and the hirsutism score, lipid levels and risk of metabolic syndrome are in between classic PCOS and phenotype - D.
Non androgenic PCOS:
This includes phenotype - D which is less severe. They have normal androgen levels with the mildest degree of endocrine dysfunction and metabolic syndrome. However, patients with high BMI may have more insulin resistance than healthy women but lower than classic PCOS.
Controlled ovarian stimulation with various Phenotypes.
AMH and AFC are high in phenotype A and C when compared to B. PCOS women with Phenotype - A are at risk of multi follicular development with more intermediary follicles on the day of trigger and hence have increased risk of Ovarian hyperstimulation syndrome (OHSS). So, they will be benefited by Gonadotropin-releasing hormone (GnRH) agonist trigger which also improves the oocyte quality and freeze all strategy. As Phenotype - B women have lower AMH and AFC than other phenotypes and are resistant PCOS; they require a higher starting dose of gonadotropins.
HA and ovulatory dysfunction have a more negative impact on clinical pregnancy rate (CPR) and live birth rate (LBR) when compared to control group. So, CPR and obstetric outcomes are better with phenotype - D.
Timely identification of these specific phenotypes helps in determining individual treatment strategies and prevent long term health sequale. They also help clinicians to identify women at high risk for Ovarian hyperstimulation syndrome (OHSS) and so can customize therapy and triggering agent.