The connection or lack there of, of IBS and menstruation is a subject of much controversy. Many women report an intensification of symptoms in their IBS during their period, but the exact cause is still up for debate.

The connection between stress and IBS is essentially agreed upon by medical professionals. Stress is an important factor in IBS because of the myriad of connections between the brain and the intestines. Although doctors don’t claim to fully understand this connection yet, there is a link between mild digestive upsets and IBS. Just as stress can cause an upset stomach in healthy people, those with IBS feel the same thing but to a much greater degree. It’s believed that the added stress related to menstruation can also be a trigger to additional symptoms.

The female reproductive hormones are also considered to be a likely trigger for IBS symptoms. A disproportionate number of IBS patients are female, so an obvious connection can be made.

The role of hormones and IBS is not yet fully understood. Menstruation has a high likelihood of worsening symptoms, while pregnancy or menopause can either makes symptoms worse or improve them. Studies that have looked at hormone replacement therapy and IBS show a link of increased case development.

Most women, IBS sufferers or not, report a change in bowel habit throughout their menstrual cycle. As with essentially every other aspect of IBS, these changes vary from women to woman. It appears as if the changing levels of the sex hormones oestrogen and progesterone result in changes to the speed of movement of contents through the intestinal tract.

During the menstrual cycle there are two phases. The follicular phase between days 6 and 11 during which time ovulation happens is noted for rising levels of oestrogen and low levels of progesterone. And the luteal phase between days 16-21, just before menstruation during which there is a measurable rise in progesterone levels.

Research has shown that the time it takes for food to digest and pass through the body is more or less the same during both these phases. Making it unlikely that women, on the whole, will report any notable change in transit time or bowel habits leading up to or just before their period.

During actual menstruation, however, things change. Many women, especially those that are constipated, experience more frequent bowel habit during menstruation.

Many different studies have shown that menstruation does have a negative effect on IBS symptoms and show that almost 50% of IBS sufferers report that their symptoms get worse during their periods.

The most common complaints during the period is an increase in gas, abdominal pain and diarrhoea. It was once strongly believed that this might be purely psychological, but the sheer amount of objective studies that have been done have disproved that belief.