Progesterone and the gut

The intricate relationship between hormones, the immune system, and gut health is becoming increasingly recognised—especially in women, whose hormonal shifts can have profound effects on both physical and emotional wellbeing. One hormone in particular, progesterone, plays a key role in modulating immune responses and gastrointestinal function. A better understanding of this hormone’s influence offers new insight into why conditions like irritable bowel syndrome (IBS) are more common—and often more severe—in women, especially after menopause.

Progesterone, the Menstrual Cycle, and IBS

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder characterised by chronic or recurrent abdominal pain, altered bowel habits, and the absence of structural or biochemical abnormalities. Symptoms often emerge in late adolescence and affect women 3 to 20 times more frequently than men. In women, IBS symptoms frequently recur in a cyclical pattern, exacerbating during the post-ovulatory (luteal) and premenstrual phases of the menstrual cycle, indicating a significant hormonal influence.

Women commonly report constipation during the progesterone-dominant luteal phase and experience looser stools or diarrhoea immediately before or at the onset of menstruation. This pattern aligns with the known effects of progesterone on the gastrointestinal system, including reduced lower esophageal sphincter tone, delayed gastric emptying, and slower intestinal transit. Progesterone may also act as an endogenous antagonist of enteric nerve function, while its abrupt withdrawal around menstruation may trigger increased bowel activity.

Prostaglandins, which rise at the start of menstrual flow, are potent stimulants of colonic contractility. Women with IBS, whose colons are hyperresponsive to stimuli, often experience exaggerated bowel responses to prostaglandins released during menstruation. This explains why abdominal pain, diarrhoea, and constipation often worsen at the onset of menses.

Progesterone’s Role in the Immune System

While progesterone is primarily known for its role in reproduction, it also has powerful effects on the immune system. Research shows that it tends to suppress inflammatory responses, promoting immune tolerance and reducing overactivity. One key mechanism is its ability to inhibit mast cell activation—these are immune cells that release histamine and other substances involved in inflammation and allergic reactions. When mast cells are overly active, they can contribute to chronic inflammatory conditions, including those affecting the gut.

By limiting mast cell secretion, progesterone helps to maintain a calmer immune environment, particularly in mucosal tissues like the gut lining. This might help explain why some women experience fewer digestive symptoms during certain phases of their menstrual cycle, when progesterone levels are naturally higher.

The Gut, Hormones, and Immune Crosstalk

The gut is home to a complex network known as the enteric nervous system, often referred to as the “second brain.” This system is closely connected to both immune function and hormone signaling. Disruptions in this network—whether from hormonal changes, chronic stress, or immune system imbalances—can trigger or worsen digestive symptoms.

For women, fluctuations in progesterone levels over the course of the menstrual cycle and across the lifespan seem to influence how sensitive the gut is to pain, inflammation, and stress. When progesterone levels are sufficient, they can help protect against gut-related discomfort. But when they drop—as they do before menstruation or after menopause—symptoms may become more pronounced.

Premenstrual exacerbation vs PMS

It is important to distinguish premenstrual exacerbation of IBS from premenstrual syndrome (PMS) or premenstrual dysphoric disorder (PMDD). While IBS symptoms—such as abdominal pain, bloating, constipation, or diarrhea—often worsen in the luteal phase due to progesterone-dominant effects on gut motility and increased colonic sensitivity to prostaglandins, PMS and PMDD primarily involve mood, sleep, and somatic changes like breast tenderness or fatigue. Women with IBS may notice that their bowel symptoms fluctuate predictably with their menstrual cycle, independent of the emotional or systemic symptoms of PMS or PMDD. Recognising this distinction is crucial for tailoring treatment, as interventions targeting gut motility and prostaglandin activity may improve IBS symptoms without necessarily affecting mood-related premenstrual disorders.

Why Symptoms Worsen After Menopause

IBS is more common in women than men, and hormone fluctuations play a large part in this. Notably, women often report that their IBS symptoms worsen after menopause. This is likely related to the sharp decline in progesterone and estrogen, which removes some of the anti-inflammatory and immune-modulating effects these hormones provide.

Postmenopausal women may experience more severe abdominal pain, bloating, and irregular bowel habits, all of which point to a heightened sensitivity and altered gut motility—both of which are strongly influenced by hormonal balance.

Implications for IBS Management

These findings suggest that hormonal status, particularly progesterone levels, should be considered when managing IBS in women. For some, especially after menopause, hormone replacement therapy (HRT) might offer relief from digestive issues in addition to addressing hot flushes, mood swings, and sleep disturbances. However, HRT isn’t appropriate for everyone, and decisions should be made with the support of a knowledgeable healthcare provider.

In addition to medical options, lifestyle factors can support healthy progesterone levels. These include stress management, regular physical activity, maintaining a balanced weight, and ensuring sufficient intake of nutrients like magnesium and vitamin B6, which support hormone production and balance.

The Takeaway

Progesterone plays a surprisingly powerful role in gut health by regulating immune responses and calming inflammation. As progesterone levels change—whether cyclically or permanently after menopause—so too can symptoms like abdominal pain, bloating, and bowel irregularities. Recognising this connection opens up new possibilities for more personalised and effective approaches to managing IBS and other digestive issues in women.

• Can my IBS symptoms get worse before my period?

  Yes. Many women with IBS notice that abdominal pain, bloating, constipation, or diarrhoea worsen in the luteal phase (the two weeks before menstruation). This is linked to higher progesterone levels slowing gut motility and increased sensitivity to prostaglandins, which stimulate the colon during menstruation.

• How do I know if my premenstrual symptoms are IBS-related or PMS/PMDD?

  IBS-related symptoms are mainly gastrointestinal—pain, bloating, constipation, or diarrhoea—that fluctuate predictably with your menstrual cycle. PMS/PMDD involves mood changes, irritability, fatigue, sleep disturbances, and breast tenderness. It’s possible to experience both simultaneously, but distinguishing them helps guide treatment.

• Should I speak to my doctor if my IBS worsens around my period?

  Absolutely. A healthcare provider can help differentiate IBS from PMS/PMDD, discuss targeted treatments, and ensure there are no other underlying gastrointestinal conditions. Keeping a detailed symptom diary can make this discussion much more effective.

About the Author

Dr Georgina Standen is a Women’s Health GP and Medical Director of Sirona Health. She specialises in the diagnosis and treatment of PMS (premenstrual syndrome) and PMDD (premenstrual dysphoric disorder), as well as broader hormonal health and menopause care. Her approach blends evidence-based medicine with personalised, compassionate support to help women regain control of their health and wellbeing.

Sirona Health offers PMS and PMDD consultations in Stroud, Cirencester, Tetbury, Fairford, Lechlade, Calne, Corsham, Chippenham, Malmesbury and Bath, along with nationwide secure online appointments.

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