PCOS, or polycystic ovary syndrome, is a common hormone disorder that affects women. PCOS causes a variety of symptoms, including irregular periods, excess hair growth, acne, and obesity. One of the key questions about PCOS is whether it is something that women are born with or something that develops later in life. There is still debate within the medical community about the origins of PCOS. However, research suggests that there are likely both genetic and environmental factors that contribute to the development of PCOS.
Is PCOS genetic?
There is strong evidence that genetics play an important role in PCOS. Studies have found that PCOS runs in families and have identified several gene variants that are associated with an increased risk of developing PCOS:
- Studies of sisters and mothers of women with PCOS show higher rates of PCOS than the general population.
- Twin studies have found that the twin sister of a woman with PCOS has a higher risk of also having PCOS.
- Variants in genes related to insulin resistance, ovarian and adrenal gland function, and more have been linked to increased PCOS risk.
The genetic component appears to be inherited in an autosomal dominant pattern, meaning that the PCOS gene can be passed down by just one parent. However, the genetics of PCOS are complex – researchers believe there are likely multiple genes involved, rather than just one. Having a particular gene variant may increase susceptibility but does not guarantee that PCOS will develop. This indicates that genetics alone cannot explain everything about PCOS – lifestyle and environmental factors also play an important role.
Does PCOS develop later in life?
While genetics may predispose someone to PCOS, research shows that lifestyle and environmental factors are major contributors to the development of the full-blown syndrome. PCOS symptoms often begin during puberty or soon after, suggesting that hormonal and metabolic changes during adolescence may trigger abnormal hormone production. Several factors have been associated with increased risk of developing PCOS around puberty or later in life:
- Obesity: Excess weight, especially excess belly fat, increases the risk for PCOS. Obesity contributes to insulin resistance, inflammation, and altered hormone production, which may all promote PCOS development.
- High androgen levels: Women with PCOS tend to have elevated male sex hormones (androgens) like testosterone. High androgens may be an inherited trait or caused by factors like obesity. Too much testosterone interferes with normal ovulation and menstrual cycles.
- Inflammation: Chronic low-grade inflammation is common in PCOS and may trigger hormonal imbalances. Inflammation may be caused by obesity, poor diet, chronic stress, environmental toxins, and more.
- Insulin resistance: Insulin resistance is present in around 80% of women with PCOS. The cells’ inability to respond normally to insulin promotes excess testosterone production by the ovaries.
- Environmental toxins: Exposure to certain pesticides, plastics, and other environmental chemicals may contribute to hormonal disruption and increase the risk for PCOS.
The influence of these environmental factors on PCOS risk indicates that genetics alone cannot fully explain PCOS – lifestyle and environmental exposures, especially during puberty, appear to interact with genetic vulnerabilities to trigger PCOS.
Is PCOS present at birth?
Because PCOS symptoms typically begin during adolescence, it was long thought that women are not actually born with PCOS – rather, they are born with a genetic susceptibility that leads to PCOS later combined with environmental triggers. However, emerging research suggests there may be subtle signs of PCOS that are actually present from birth or infancy:
- One study found metabolic differences in umbilical cord blood between babies born to women with and without PCOS.
- Some research indicates girls born to mothers with PCOS may have slightly altered hormone levels early in life.
- A few small studies have suggested that girls who go on to develop PCOS show some differences in metabolic markers in infancy and childhood compared to healthy girls.
While none of these findings are definitive, they suggest the earliest stages of PCOS may actually be present at birth or shortly after in girls genetically predisposed to the condition. Larger, long-term studies that follow girls from birth to adulthood are still needed to confirm this. Most experts maintain that the full syndrome does not typically arise without the hormonal changes of puberty and environmental exposures.
When does PCOS start?
Based on the current evidence, here is the general timeline for when PCOS arises:
- Genetic susceptibility: Inherited either from the mother or father, often runs in families.
- Metabolic abnormalities begin: Subtle insulin resistance, inflammation, and androgen elevation may be present at birth or develop in early childhood.
- Changes accelerate at puberty: Hormonal fluctuations at puberty appear to interact with genetic risks and metabolic issues, triggering the beginning of characteristic PCOS signs like irregular periods, cystic ovaries, and symptoms like acne and hair growth.
- Syndrome develops: The typical features of PCOS fully develop during the reproductive years, often exacerbated by environmental factors like obesity, poor diet, stress, and toxins.
In summary, while genes that predispose to PCOS may be present from the beginning, most experts believe the full-blown syndrome does not typically arise until hormonal shifts during adolescence activate these genetic risks. Environmental factors often play a major role during puberty and the reproductive years in triggering the development of the classic PCOS signs and symptoms.
Can lifestyle interventions prevent PCOS development?
Since lifestyle factors like obesity, diet, and activity levels clearly influence the development of PCOS in those with a genetic predisposition, an important question is whether interventions aimed at these modifiable risk factors could help prevent PCOS from fully manifesting. Some promising research in adolescent girls suggests the answer may be yes:
- One study found that adolescent girls at high risk for PCOS who completed an intervention focused on improving diet, exercise, and sleep saw improvements in insulin sensitivity and other metabolic markers compared to controls.
- Another study found that overweight girls who lost weight through a structured weight management program had lower androgen levels and reduced PCOS symptoms compared to girls who did not lose weight.
While larger and longer studies are still needed, these results indicate that lifestyle and environmental optimization during adolescence may help delay or prevent the full development of PCOS in susceptible girls. Proactively improving diet, activity, weight, and other modifiable factors early in life could potentially lower PCOS risk in those born with a genetic predisposition.
The role of epigenetics
Emerging research suggests that epigenetics may also play a role in the development of PCOS. Epigenetics refers to changes that alter how genes are expressed without changing the underlying DNA code. Environmental influences like diet, toxins, stress, and other exposures can cause epigenetic changes, especially during critical developmental windows like puberty.
Evidence suggests that epigenetic changes influencing how important genes are turned on or off may contribute to the metabolic and hormonal disturbances characteristic of PCOS:
- Studies have found altered methylation patterns of genes involved in insulin signaling, ovarian steroidogenesis, inflammation, and more in women with PCOS.
- Environmental toxins like BPA may increase PCOS risk by disrupting epigenetic expression of genes involved in reproductive function.
- Diet and nutrition likely induce epigenetic changes that influence PCOS as well – for example, high sugar intake promotes inflammation, which can cause epigenetic changes that exacerbate PCOS.
While still an emerging area of science, understanding these epigenetic factors may provide additional opportunities to prevent passing down the risk of PCOS to the next generation or potentially reduce the risk of developing PCOS through dietary and lifestyle interventions that optimize the epigenome.
The takeaway
The development of PCOS is complex and not yet fully understood, but likely involves the interplay of genetic vulnerabilities, hormonal factors, lifestyle habits, and environmental exposures. While an inherited predisposition appears to be necessary, most experts believe environmental triggers during adolescence are also required for the syndrome to fully manifest. There may be subtle metabolic or hormonal abnormalities present at birth that then accelerate into full-blown PCOS during puberty. Lifestyle interventions and epigenetic factors may help reduce risk in genetically susceptible girls and women. While PCOS cannot yet be prevented or cured, identifying opportunities to intervene early and optimize modifiable factors may help improve outcomes in those born with a predisposition.
Conclusion
In summary, current evidence suggests that PCOS arises from a combination of genetic susceptibility present from before birth and hormonal/environmental influences that accumulate overtime, especially around puberty. Women are likely born with certain PCOS-related genetic variants, but the characteristic signs and symptoms typically don’t arise until adolescence, when hormonal shifts appear to interact with genetic risk and lifestyle factors to trigger the full spectrum of PCOS features. While some subtle metabolic abnormalities may be detectable earlier in life, most experts believe the syndrome is not fully present at birth – rather, it develops over time influenced by both nature (genetics) and nurture (environment and exposures). Interventions aimed at improving modifiable risk factors like obesity, diet, and physical activity in genetically susceptible individuals may help delay or prevent the onset of the full-blown clinical syndrome. Ongoing research is still needed to better unravel the complex interplay between genes, hormones, and environment that lead to PCOS.