IBS is significantly more common in women than men — affecting women at roughly twice the rate. This disparity is not coincidental. Hormones play a direct and powerful role in gut function, and the hormonal fluctuations that women experience throughout their lives have measurable effects on IBS symptoms.
The Menstrual Cycle and IBS
Many women with IBS notice that their symptoms worsen at specific points in their menstrual cycle — particularly in the days before and during menstruation. This is not psychological. Prostaglandins released during menstruation directly stimulate gut muscle contractions, increasing urgency and diarrhoea symptoms. Simultaneously, progesterone levels drop sharply, which affects gut motility and can trigger constipation in the luteal phase.
Oestrogen and the Gut Microbiome
Oestrogen has a significant protective effect on gut microbiome diversity. Research shows that higher oestrogen levels are associated with greater gut bacterial diversity, lower levels of gut inflammation and reduced IBS symptom severity. This helps explain why many women experience worsening IBS symptoms during perimenopause and after menopause, when oestrogen levels decline.
Perimenopause, Menopause and IBS
The menopausal transition is a major gut health event for many women — even those who have never had significant gut issues before. New or worsening IBS-like symptoms during perimenopause are common and directly related to oestrogen decline. Women who already have IBS often experience significant symptom escalation during this period.
Nutritional Support
Protein intake is particularly important during hormonal transitions. Oestrogen supports muscle protein synthesis, so its decline means muscle — including the smooth muscle of the gut wall — requires more dietary protein to maintain. Adequate certified Low FODMAP protein intake directly supports gut wall integrity during these transitions.