Endo Belly and Perimenopause: Is It Your Hormones or Something Else?

You've lived with endometriosis for years. You know your patterns, your triggers, your bad weeks. And then you hit your 40s — and suddenly none of it makes sense anymore.

The bloating is worse. It's less predictable. It's showing up on days it never used to. And somewhere in the back of your mind is a question you haven't quite said out loud: is this still my endo — or is perimenopause layering on top of it?

The honest answer, clinically, is: probably both.

Why the 40s change the picture

Endometriosis is an oestrogen-dependent condition — the tissue growth and inflammation it causes are driven, in part, by circulating oestrogen. Perimenopause is defined by exactly that: oestrogen doing anything but staying steady. It surges, dips, and swings unpredictably for years before periods stop altogether.

Put those two things in the same body, and you get a bloating pattern that's harder to predict than ever. What I see time and again in clinic is women in their early-to-mid 40s who assume they've simply "gotten worse" at managing their endo, when actually their whole hormonal landscape has shifted underneath a condition they thought they already understood.

The overlap, symptom by symptom

Bloating that no longer follows your cycle. Your endo belly might have reliably shown up the week before your period for fifteen years. In perimenopause, cycles themselves become irregular — so the bloating stops following the calendar you'd learned to trust.

New fluid retention. Perimenopause brings its own bloating driver: falling progesterone makes it harder for your body to shed excess fluid, independent of anything endometriosis-related. This can stack directly on top of existing endo inflammation.

Slower digestion. Oestrogen fluctuation affects gut motility on its own — so on top of the visceral sensitivity endometriosis already causes, perimenopause can slow things down further, adding constipation and gas into the mix.

Increased sensitivity generally. Chronic inflammation from endometriosis can lower your pain threshold over time. Add perimenopausal hormone swings, and normal digestive sensations can feel more intense than they used to — even on a genuinely unremarkable day.

Why this matters for what you do next

If you're only treating this as "my endo, as usual," you may be missing half the picture — and wondering why old strategies aren't working the way they once did. If you're only treating it as "perimenopause," you risk overlooking a hormonal-inflammatory pattern that's been present for years and still needs its own support.

As a registered medical herbalist (MNIMH), this is exactly the kind of layered pattern I work with — supporting the hormonal picture as a whole, rather than treating each label in isolation. The two conditions interact; the support usually needs to as well.

Working out what's actually going on

If your bloating has changed in your 40s and you're not sure whether it's your endo, perimenopause, or both, my quiz is a good place to start untangling it.

[Take the quiz: Where Do I Start? →]

Marie Mulcahy is a NIMH-registered Medical Herbalist (MNIMH) specialising in hormone health, working with women across Lancashire and UK-wide via online consultation.