Could Early-Life Experiences Influence PCOS/PMOS Risk?

What Did The Study Involve?

The study used health information from 272,706 women participating in the UK Biobank.

The researchers examined whether six early-life factors were associated with:

• PCOS
• Endometriosis
• Uterine fibroids
• Female infertility
• Premenstrual syndrome
• Genital prolapse

A total of 947 women in the study had a recorded diagnosis of PCOS.

The researchers adjusted their results for several factors that may otherwise influence the findings, including age, ethnicity, education, socioeconomic disadvantage, and smoking status.

Recurrent Antibiotic Use Was Associated With Higher Odds Of PCOS/PMOS

Women who reported regularly using antibiotics during childhood or adolescence had almost twice the odds of having PCOS compared with women who did not report this history.

In this study, long-term or recurrent use was defined as receiving three or more courses of antibiotics per year during childhood or the teenage years.

This was one of the strongest PCOS-related associations identified in the research.

However, this does not mean antibiotics directly caused PCOS/PMOS.

Frequent antibiotic use may also reflect other factors, such as:

• Recurrent childhood infections
• Differences in immune function
• Underlying inflammation
• Healthcare access and prescribing practices
• Other environmental or socioeconomic influences

The researchers were not able to separate these possibilities.

Could The Gut Microbiome Be Involved?

One possible explanation raised by the researchers involves the gut microbiome.

Antibiotics can reduce harmful bacteria, which is why they are such an important medical treatment. However, they can also temporarily or sometimes more persistently alter beneficial gut bacteria.

The gut microbiome is involved in several processes that may be relevant to PCOS/PMOS, including:

• Inflammation
• Insulin function
• Immune regulation
• Metabolism
• The processing and recycling of hormones such as oestrogen

The researchers suggested that repeated disruption of the gut microbiome during important stages of development could potentially influence hormone or metabolic health later in life.

However, the study did not directly measure participants’ gut bacteria. This explanation is therefore only a theory and cannot be confirmed from this research.

The “Estrobolome” May Help Connect Gut And Hormone Health

The paper also discussed the estrobolome.

The estrobolome is the collection of gut bacteria involved in processing and regulating oestrogen.

Changes to these bacteria may affect how oestrogen is metabolised and circulated throughout the body.

Because reproductive hormones, insulin, inflammation, and the gut microbiome all communicate with one another, disturbances during early development could theoretically influence reproductive health many years later.

Again, this study did not test the estrobolome directly. It simply offers one possible biological pathway that future research may investigate.

Earlier Menstruation Was Also Linked With PCOS/PMOS

Women who had their first menstrual period at age 12 or younger had approximately 30% higher odds of PCOS compared with women whose periods began after age 12.

When the researchers examined age more closely, menstruation beginning before age 12 showed an even stronger association with PCOS.

Women who started menstruating before age 12 had approximately 64% higher odds of PCOS than women who began at age 13.

This does not mean that an early first period causes PCOS/PMOS.

Age at the first period may instead be an early sign of underlying hormonal, metabolic, genetic, or environmental influences that are also involved in PCOS/PMOS.

Puberty May Be An Important Window For Hormone Health

Puberty is a major stage of hormonal and metabolic development.

During this time, the brain, ovaries, adrenal glands, insulin system, and reproductive hormones are all adapting.

An earlier first period may reflect differences in:

• Insulin sensitivity
• Body composition
• Hormone exposure
• Genetic factors
• Nutrition
• Environmental exposures
• The timing of reproductive development

The study suggests that the timing of puberty may provide useful information about later reproductive health, although it cannot tell us exactly why the association exists.

Not Every Early-Life Factor Was Linked With PCOS/PMOS

The study did not find statistically significant associations between PCOS and:

• Birth weight
• Being breastfed as a baby
• Maternal smoking around the time of birth
• Being a twin, triplet, or part of another multiple birth

This is important because the paper examined several possible influences, but only recurrent antibiotic use and earlier menstruation were clearly associated with PCOS in the main analysis.

These other early-life factors were associated with some of the different gynaecological conditions examined, but not specifically with PCOS.

Early Life May Shape Later Metabolic Health

The findings support a wider concept known as the Developmental Origins of Health and Disease.

This theory suggests that conditions during pregnancy, infancy, childhood, and puberty may influence how the body’s organs and metabolic systems develop.

Early-life experiences may affect areas such as:

• Insulin sensitivity
• Hormone production
• Immune function
• Inflammation
• Gut health
• Ovarian development

These changes may not cause a health condition on their own. Instead, they may contribute to a person’s overall susceptibility when combined with genetics and later environmental or lifestyle influences.

This Is About Risk, Not Blame

Research into early-life exposures can feel confronting because these are factors we often cannot remember, control, or change.

It is important to understand that this study is not suggesting that parents caused PCOS/PMOS, that antibiotics should have been avoided when medically necessary, or that an early period guarantees future hormone problems.

PCOS/PMOS is a complex condition shaped by many interacting factors.

These can include:

• Genetics
• Insulin resistance
• Androgen production
• Inflammation
• Stress physiology
• Environmental exposures
• Reproductive development

An early-life factor may form one small part of that bigger picture.

The Antibiotic Finding Needs Further Research

Although the association between recurrent antibiotic use and PCOS was strong in the primary analysis, it became less certain when the researchers removed self-reported PCOS cases and looked only at other diagnostic records.

This means the finding should be interpreted carefully.

The study also relied on adults remembering how often they had used antibiotics many years earlier. Memories may not always be accurate, and the researchers did not know:

• Which antibiotics were taken
• The exact doses
• How long each course lasted
• The infections being treated
• Whether antibiotic exposure occurred before PCOS began developing

The results are interesting, but they are not strong enough to recommend avoiding necessary antibiotics or using microbiome treatments to prevent PCOS.

The Study Cannot Prove Cause And Effect

This was an observational study.

It can identify patterns between early-life experiences and adult health, but it cannot prove that one directly caused the other.

Other limitations include:

• Only 947 women had a recorded PCOS diagnosis
• PCOS is commonly underdiagnosed
• Several early-life factors were recalled many years later
• The participants were predominantly of White British background
• Some PCOS diagnoses were self-reported
• The study did not directly measure hormones, insulin, inflammation, or gut bacteria

The researchers described the potential biological explanations as theories that need to be tested in future studies.

Why This Research Still Matters

Despite its limitations, this study adds another piece to the PCOS/PMOS puzzle.

It suggests that PCOS/PMOS may not suddenly begin when symptoms become obvious in adulthood.

Instead, susceptibility may develop gradually through a combination of:

• Genetics
• Early hormonal development
• Metabolic health
• Immune and inflammatory influences
• Environmental exposures
• Experiences during puberty

This may help explain why PCOS/PMOS looks so different from one person to another and why no single cause or treatment applies to everyone.

What Does This Mean For PCOS/PMOS?

This research suggests that PCOS/PMOS susceptibility may begin developing long before symptoms become obvious.

Women who reported recurrent antibiotic use during childhood or adolescence had higher odds of PCOS, while starting menstruation at age 12 or younger was also associated with increased odds.

Possible explanations include changes involving the gut microbiome, inflammation, insulin function, hormone metabolism, and reproductive development. However, the study cannot prove that antibiotics or earlier menstruation directly cause PCOS/PMOS.

The key message is not that childhood experiences determine your future. Instead, this research helps us understand that PCOS/PMOS may be shaped by a combination of genetics, hormones, metabolism, environment, and development across the life course.

We cannot change our early-life experiences, but we can continue supporting the areas that remain within our influence, including insulin sensitivity, inflammation, gut health, stress, nutrition, and overall metabolic health.