BPA, xenoestrogens, and perimenopause

There is a phrase that sounds simple, but opens a huge question:

your perimenopause does not necessarily begin when the first hot flashes appear.

Part of the biological terrain may have formed much earlier: in fetal life, childhood, puberty, and adolescence.

That does not mean everything is decided from birth. It also does not mean one chemical exposure explains every symptom. But recent research on BPA, phthalates, parabens, and other xenoestrogens points to something important: some external molecules can interfere with the system that interprets hormones.

Not only with the amount of estrogen.

With tissue sensitivity.

With ovarian reserve.

With the stress-axis response.

With the epigenetic marks that help decide which genes are expressed, when, and in which tissue.

What xenoestrogens are

Xenoestrogens are compounds outside the body that can interact, directly or indirectly, with hormonal pathways.

The best-known example is BPA, historically used in plastics, resins, and packaging. There are also alternatives such as BPS, BPF, and other bisphenols. Add to that phthalates, parabens, and multiple compounds capable of acting as endocrine disruptors.

The word "xenoestrogen" can give an incomplete idea. They do not always act as a simple copy of estradiol.

They can influence:

• estrogen receptors such as ESR1 and ESR2;
• receptors such as GPER, AhR, or PPAR;
• steroidogenesis;
• oxidative stress;
• inflammation;
• oocyte maturation;
• adipose tissue metabolism;
• epigenetic machinery such as DNMT, TET, HDAC, histones, and microRNAs.

That is why the question is not only "does estrogen go up or down?".

The more precise question is:

does the way the body listens to the hormonal signal change?

The window matters more than the isolated dose

In endocrinology, the timing of exposure can matter as much as the dose.

An exposure during a critical window can have a different effect than the same exposure years later. Fetal life, childhood, and puberty are stages when the reproductive system, adipose tissue, stress axis, and hormonal sensitivity are still being calibrated.

Set-points are formed there:

• how many follicles survive;
• how granulosa cells respond to FSH and oocyte signals;
• how estrogen sensitivity is regulated;
• how the HPA axis, related to cortisol, matures;
• how adipose tissue is distributed and responds;
• when puberty and menarche happen.

That context is key to understanding why a symptom at 47 does not always begin at 47.

It may be the late expression of a system that reaches the hormonal transition with more or less room to adapt.

What recent evidence shows

A review by Peters and collaborators published in Human Reproduction Update analyzed 107 studies on BPA and alternatives in oocytes and follicles. Most in vitro and in vivo studies found some adverse effect on oocyte or follicular health, including changes in maturation, meiotic spindle, chromosomal alignment, morphology, and follicular development.

The responsible reading is not "all plastic causes infertility".

The responsible reading is that the ovary and follicle are sensitive to external chemical signals, and that some BPA-free alternatives should not be assumed to be biologically neutral.

In humans, Blaauwendraad and collaborators studied exposure to bisphenols and phthalates during pregnancy and anti-Mullerian hormone levels years later. BPA did not show a significant association with AMH, but several phthalate metabolites were associated with lower AMH in longitudinal models.

This does not prove causality. But it does change the conversation: the reproductive exposome could be related to the pace of ovarian reserve, not only to immediate fertility.

Another study, by Khodasevich and collaborators, analyzed prenatal exposure to phenols and phthalates and DNA methylation patterns in childhood and adolescence. They found sex-specific associations and some marks that persisted until ages 9 and 14.

In other words: certain prenatal exposures could leave a measurable trace long after the original compound has already disappeared from the body.

The epigenetic layer

Epigenetics does not change the DNA sequence. It changes the way that DNA is regulated.

It is a layer of instructions: which genes open, which are silenced, when they activate, and in which tissue.

For female hormonal health, that matters because hormones do not act in a vacuum. They need receptors, cofactors, available chromatin, and tissues capable of responding.

The same hormonal concentration can feel different if the tissue responds differently.

That is the central point.

Early xenoestrogens may not create a linear disease. They could narrow the system’s adaptive range. Years later, when ovarian stability declines in perimenopause, that terrain can become visible.

Three biological memories

At Lua Labs, we are thinking about this as a three-memory model.

early xenoestrogens
  -> hormone receptors + oxidative stress + epigenetic machinery
  -> ovarian memory, receptor memory, and metabolic memory
  -> perimenopause with less room to adapt

The first is ovarian memory.

During fetal life and early stages, the follicle and oocyte can be sensitive to signals that alter maturation, granulosa-oocyte communication, atresia, and functional reserve.

The second is receptor memory.

It is not enough to have estradiol or estrone. Tissue has to hear them. If estrogen receptor sensitivity is altered by chromatin, inflammation, or early programming, the same hormone can produce a different response.

The third is metabolic memory.

Adipose tissue also responds to hormonal signals. It can become inflamed, change insulin sensitivity, modify aromatase, and participate in peripheral estrogen production. In perimenopause, when the ovary stops dominating the conversation, that tissue can speak louder.

Why this matters in perimenopause

Perimenopause is not just "low estrogen".

It is variability.

Less consistent progesterone. Irregular estradiol. More sensitivity to broken sleep. Changes in hunger, nighttime heat, energy, mood, and body composition.

If a woman reaches this stage with lower adaptive reserve in the ovary, receptors, adipose tissue, or stress axis, the transition can feel louder.

That could help explain why two women of the same age, with similar labs, experience the transition in completely different ways.

One has moderate symptoms.

Another has insomnia, hot flashes, brain fog, reactive hunger, erratic cycles, and fatigue.

Not because one "can’t handle it as well".

Because the system that interprets the hormonal signal may be different.

BPA-free does not always mean hormonally neutral

One delicate part of this conversation is marketing.

"BPA-free" sounds like the problem is closed. But several BPA alternatives have also shown biological activity in experimental studies.

That does not mean every BPA-free product is dangerous. It means we cannot confuse a commercial label with endocrine neutrality.

The right scientific question is:

what compound replaced it, and what does it do in real hormonal systems?

What we cannot say

We cannot say that BPA causes perimenopause.

We cannot say that a symptom comes from a specific exposure.

We cannot say that an app can diagnose methylation, ovarian reserve, or xenoestrogen load.

We cannot say "detox" as if the body reset itself with a list of foods.

The honest version is more sober:

there is enough evidence to take early exposure windows, hormonal tissue sensitivity, and the possibility that some biological traces express themselves years later seriously.

That already changes the questions we should be asking.

What questions do matter

Without falling into chemical panic, there are useful questions:

• when was your menarche?
• did you grow up near intensive agriculture, factories, workshops, nail salons, or cleaning businesses?
• during your childhood, was food often heated in plastic containers?
• was there high consumption of canned foods, soda, or ultra-processed foods during childhood or adolescence?
• have you used many fragranced products, cosmetics, or nail products frequently since early stages?
• do your current symptoms amplify with poor sleep, late dinners, or more digestive inflammation?

No answer diagnoses anything.

But together, they can help contextualize why a body responds in a certain way during the hormonal transition.

The XEPS hypothesis

At Lua Labs, we proposed a conceptual marker: XEPS, for Xenoestrogen Early-life Programming Score.

It is not a clinical test.

It does not exist today as a validated score.

It is a research hypothesis to organize variables that could matter:

• inferred fetal, childhood, or pubertal exposure;
• agricultural, industrial, or chemical environment;
• early use of cosmetics or fragranced products;
• heating food in plastic during childhood;
• early or late menarche;
• current avoidable exposure;
• confidence in recall.

The future question would be whether that history improves symptom prediction alongside other patterns: sleep, food, cycle, hormonal stage, energy, mood, visceral fat, circadian rhythm, and digestive signals.

If it does not add predictive power, it is discarded or weakened.

If it adds signal, it could help us personalize better.

The useful conversation is not fear. It is precision.

Talking about endocrine disruptors can become alarmist very quickly.

It does not help to tell a woman that "everything is contaminated" or that her body is damaged.

The useful conversation is different:

your biological history can help explain your hormonal present.

Not to blame you.

Not to sell you a cleanse.

To ask better questions, identify patterns, and stop treating all bodies as if they respond the same way.

Because maybe perimenopause is not only the moment when hormones change.

It may also be the moment when the body reveals how it learned to listen to them.

Sources

• Peters AE, Ford EA, Roman SD, Bromfield EG, Nixon B, Pringle KG, Sutherland JM. Impact of Bisphenol A and its alternatives on oocyte health: a scoping review. Human Reproduction Update. 2024. DOI: 10.1093/humupd/dmae025.
• Blaauwendraad SM, Dykgraaf RHM, Gaillard R, Liu M, Laven JS, Jaddoe VWV, Trasande L. Associations of bisphenol and phthalate exposure and anti-Mullerian hormone levels in women of reproductive age. EClinicalMedicine. 2024. DOI: 10.1016/j.eclinm.2024.102734.
• Khodasevich D, Holland N, Harley KG, Eskenazi B, Barcellos LF, Cardenas A. Prenatal exposure to environmental phenols and phthalates and altered patterns of DNA methylation in childhood. Environment International. 2024. DOI: 10.1016/j.envint.2024.108862.
• Chen J, et al. The Role of Placental DNA Methylation at Reproduction-Related Genes in Associations between Prenatal Bisphenol Analogues Exposure and the Digit Ratio in Children at Age 4: A Birth Cohort Study. Environmental Science & Technology. 2024. DOI: 10.1021/acs.est.4c01791.
• Freire C, Castiello F, Babarro I, Anguita-Ruiz A, Casas M, Vrijheid M, et al. Association of prenatal exposure to phthalates and synthetic phenols with pubertal development in three European cohorts. International Journal of Hygiene and Environmental Health. 2024. DOI: 10.1016/j.ijheh.2024.114418.
• Jedynak P, Bustamante M, Rolland M, Mustieles V, Thomsen C, Sakhi AK, et al. Prenatal exposure to synthetic phenols assessed in multiple urine samples and dysregulation of steroid hormone homeostasis in two European cohorts. Environmental Health Perspectives. 2025. DOI: 10.1289/EHP15117.
• Li M, Wu Y, Wei S, Zhang T, Yan W, Gao Y, et al. Transgenerational inheritance of diminished ovarian reserve triggered by prenatal propylparaben exposure in mice. Nature Communications. 2025. DOI: 10.1038/s41467-025-63440-z.
• Okon Michael Ben, Olorunnisola SO, Ifie JE, Ugwu OPC, Alum EU, Mounmbegna P, et al. Transgenerational reproductive risks of BPA: epigenetic mechanisms and biomarker applications. A critical review. Environmental Epigenetics. 2026. DOI: 10.1093/eep/dvag010.