PCOS Risk Factor


What is PCOS?

Polycystic ovary syndrome (PCOS) is a condition in which the ovaries produce an abnormal amount of androgens, male sex hormones, that are normally present in small amounts in people assigned female at birth (AFAB). It primarily affects females aged 18 to 44. The persistent hormonal imbalance causes complications such as numerous cysts, irregular menstrual cycles, and infertility in females. The precise cause of PCOS is unknown.


Not all people AFAB with PCOS will experience all of the symptoms, and each symptom can range from mild to severe. Some may only have menstrual problems, while others are unable to conceive.

Common symptoms of PCOS include:

  • irregular periods or no periods at all
  • infertility (because of irregular ovulation or no ovulation)
  • excessive hair growth (hirsutism) – most commonly on the face, chest, and arms
  • weight gain
  • Hair thinning or loss from the head
  • oily skin or acne

Risk factors

Family history of PCOS

PCOS is a heterogeneous disorder with a strong genetic component, and family history is considered an important factor in determining the risk of developing it. According to preliminary data, the risk of developing PCOS is approximately 40% if a sister is affected. Alternatively, only 19% of mothers were affected, implying that PCOS inheritance is preferentially paternal (through the male line), though larger clinical studies are needed to confirm these findings.1

The highly variable phenotype (presentation) of PCOS suggests that, in addition to a single genetic mutation, other factors may contribute to its development. Environmental influences such as fat and carbohydrate consumption, exercise level, prepubertal stress, and/or hormonal exposure may be among these factors. Additional genetic defects, such as those that regulate insulin secretion or determine body type, may also play a role in the clinical presentation of PCOS.


Obesity and insulin resistance are both linked to PCOS pathophysiology. Many PCOS people AFAB are overweight and resistant to insulin action in their bodies leading to more production of insulin to compensate. This results in increased hormone production and activity, such as testosterone. However, more research is needed to determine whether weight loss surgery improves fertility in people AFAB with PCOS and to determine which operation produces the best results.

Exposure to endocrine-disrupting chemicals

PCOS is a symptomatically diverse disorder with unknown aetiology, likely to involve genetic and environmental factors that work together to contribute to its phenotypic expression.

Endocrine-disrupting chemicals (EDCs), particularly Bisphenol A (BPA), are a class of widespread pollutants studied as potential environmental contributors to PCOS pathophysiology. Significant evidence from in vitro and animal studies implicates endocrine disruptors in the induction of reproductive and metabolic abnormalities resembling PCOS symptoms. In humans, elevated BPA concentrations are observed in adolescents and adult PCOS women compared to reproductively healthy women. They are positively correlated with hyperandrogenaemia (too much androgen in the blood), implying a potential role for the chemical in PCOS pathophysiology, though a causal relationship has yet to be established. 

It is possible that developmental exposure to specific EDCs could permanently alter neuroendocrine, reproductive, and metabolic regulation in genetically predisposed individuals, or it could accelerate and/or exacerbate the syndrome's natural course.3


Smoking, an important modifiable risk factor, has been linked to reproductive disorders. Cigarette smoke contains a complex mixture of chemical substances that can have multiple effects on different organs, including the ovary, fallopian tube, and uterus. The negative effects of smoking on the risk of PCOS have recently sparked a lot of research interest. 2

Abnormally long periods or short menstrual cycles

Long and irregular menstrual cycles are a feature of polycystic ovary syndrome (PCOS). Hyperandrogenaemia is linked to menstrual irregularity, hirsutism, and acne, and has been associated with an increased risk of metabolic disorders. Hyperandrogenaemia is another important indicator of PCOS. Adolescent menstrual irregularity has been shown to be a good marker of hyperandrogenaemia and has been linked to the development of PCOS in adulthood. Furthermore, adolescent girls who have irregular menstrual cycles have higher androgen levels than girls who have regular menstrual cycles. 4


One of the most common causes of female infertility is PCOS. PCOS risk factors include smoking, obesity, irregular periods and exposure to BPA. If you are concerned about PCOS, see your doctor. 


  1. Kahsar-Miller, M., & Azziz, R. (1998). The development of the polycystic ovary syndrome: family history as a risk factor. Trends in endocrinology and metabolism: TEM, 9(2), 55–58. https://doi.org/10.1016/s1043-2760(98)00021-6
  2. Tao, Y., Liu, B., Chen, Y., Hu, Y., Zhu, R., Ye, D., Mao, Y., & Sun, X. (2021). Genetically Predicted Cigarette Smoking in Relation to Risk of Polycystic Ovary Syndrome. Clinical epidemiology, 13, 527–532. https://doi.org/10.2147/CLEP.S311785
  3. Palioura, E., & Diamanti-Kandarakis, E. (2015). Polycystic ovary syndrome (PCOS) and endocrine disrupting chemicals (EDCs). Reviews in endocrine & metabolic disorders, 16(4), 365–371. https://doi.org/10.1007/s11154-016-9326-7
  4. S West, H Lashen, A Bloigu, S Franks, K Puukka, A Ruokonen, M-R Järvelin, J S Tapanainen, L Morin-Papunen (2014). Irregular menstruation and hyperandrogenaemia in adolescence are associated with polycystic ovary syndrome and infertility in later life: Northern Finland Birth Cohort 1986 study. 29 (10): 2339-51

Misha Siddiqui

Master's degree, Integrated immunology, University of Oxford, England

2nd year PhD candidate at institute of cancer research and AstraZeneca applying deep learning to understanding immunometabolism using multi-omics. I have a masters in integrated immunology from the university of oxford and undergraduate in applied medical sciences from UCL.

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