Irritable Bowel Syndrome (IBS) is predominantly diagnosed in women and approximately twice as many women have IBS compared to men.1 Females typically have constipation-predominant IBS.2 Some studies suggest that the predominance of IBS in women may be due to the presence of sex hormones.1 Women are most likely to have IBS during their late teens to mid-forties, which is when reproductive hormones are at a high level.3
Studies suggest that a women’s response to IBS symptoms may be due to declining or low ovarian hormones. The low levels of estrogen and progesterone may contribute either directly or indirectly to an increase in pain sensitivity.1 Immediately before and during their menstrual cycle, women report an increase in gastrointestinal symptoms, likely due to variations in ovarian hormone levels.1,4 Also, gastrointestinal issues may be more apparent in women, because women have slower gastrointestinal transit time compared to men, which delays bowel movements.1 The gastrointestinal symptoms reported include bowel discomfort, bloating, and alterations in bowel patterns.2 In particular, an increase in abdominal pain or discomfort is typically observed during the menstrual cycle when there are low ovarian hormone concentrations. In addition, women reported symptoms of nausea, higher symptom severity, and lower quality of life compared to men.2,5
Sex hormones may also have an effect on the body’s response to stress. In addition, females with IBS tend to have a more pronounced reaction to emotional stress.1 In addition, women reported more general anxiety.5 Stress may cause impairments in the gut’s function and ultimately contribute to IBS occurrence and symptom severity.1
Constipation is the most common complaint reported by pregnant women, which may be due to hormonal changes. Hormonal changes affect bowel function and gastrointestinal pain sensitivity. For pregnant women, there may also be a direct effect of a growing fetus on bowel function. Also, the psychological stress during pregnancy may be a trigger in pregnant women and change bowel habits.3
There aren’t a lot of studies that have examined the impact of the menopause transition on IBS patients, and the study findings have been fairly inconsistent. Although the decline in ovarian hormones may make gastrointestinal symptoms worse, generally, in postmenopausal period, the incidence of IBS decreases. However, there are also studies that show that the severity of IBS symptoms increases after menopause. In one study, gas and excessive flatulence were more prevalent in post- than premenopausal healthy women.6
Premenopausal healthy women taking certain oral contraceptives tend to report an increase in gastrointestinal symptoms during menses.6 However, in a study of women with IBS taking oral contraceptives that contain both estrogen and progestin, women taking oral contraceptives actually had reduced levels of abdominal symptoms compared with IBS women not taking oral contraceptives. At the same time, the pattern of gastrointestinal and non-gastrointestinal symptoms during a woman’s menstrual cycle was similar in female patients with IBS, regardless of use of oral contraceptives or the predominant bowel pattern.
The effect of hormone supplementation during menopause on IBS symptoms is still unclear. In postmenopausal women, hormone replacement therapy has been reported to be associated with the increased prevalence of IBS. It’s possible that hormone replacement therapy prolongs IBS symptoms or can even induce changes in gastrointestinal function in females not previously affected.
Not much is known about prevalence of oophorectomy (removal of the ovaries) or hysterectomy (removal of the uterus) in women with IBS, mostly because women with IBS who have had these surgical procedures are excluded from IBS studies.6 It has been reported, though, that twice as many women who have had a hysterectomy or oophorectomy have IBS compared to women who did not have either surgery. It’s possible that that IBS patients, because of the chronic abdominal pain, are more likely to have certain surgical procedures (not only gynecological, but also gastrointestinal surgery. In a number of women, GI symptoms emerge for the first time after gynecological surgery.