Irritable Bowel Syndrome (IBS): Issues for Your Pregnancy

Note: The Pregistry website includes expert reports on more than 2000 medications, 300 diseases, and 150 common exposures during pregnancy and lactation. For the topic Irritable Bowel Syndrome, go here. These expert reports are free of charge and can be saved and shared.


Episodes of diarrhea and/or gas, interspersed with bouts of constipation. It sounds like some effects of pregnancy and it is, but such symptoms are also characteristic of what’s called irritable bowel syndrome (IBS). This is a condition that affects approximately 10 to 15 percent of adults in the United States. Usually, it is first recognized in young adulthood, with women affected twice as often as men, so IBS is also a condition occurring during pregnancy. In the past, the condition often was called spastic colon, but this term has mostly been replaced by IBS. It is important not to confuse IBS with IBD, which stands for inflammatory bowel disease.

IBS can develop from various minor abnormalities, as opposed to gastrointestinal conditions that are linked to anatomic problems, inflammation, infection, or cancer. Basically, IBS is a diagnosis of exclusion. If doctors cannot find anything severely wrong with your digestive tract, then IBS will be the diagnosis, if you are not having normal bowel movements. The abnormalities that can cause IBS include intolerance to certain categories of carbohydrates. The abnormalities also include anxiety and similar behavioral disorders that make nervousness a trigger for an IBS attack. In all cases, IBS is characterized by abdominal pain and altered or unpredictable bowel habits, including diarrhea and constipation.

As noted above, IBS is a diagnosis of exclusion. This means that you are sent to a gastroenterologist to evaluate you for several different diseases, such as IBD, serious gastrointestinal infections, genetic disorders affecting the digestive tract, and malignancy. If all tests turn out negative, IBS is the diagnosis. Tests include blood tests and imaging. In some cases IBS may be the result from minor enzyme deficiencies, such as a lactose deficiency (inability to digest milk sugar) or what is called fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) intolerance. This means that you have trouble digesting any of a range of carbohydrates. In either case, the condition may be controlled at least partly through control of the diet.

Because of the growing womb, pregnancy can exacerbate IBS. Diarrhea caused by IBS furthermore can aggravate hemorrhoids, which themselves are provoked by pregnancy. If your digestive disturbance comes at night, which it often does with IBS, this could cause you to go to sleep later than planned. Combined with a schedule that requires you to wake early in the morning, this can lead to inadequate sleep.

IBS is treated symptom by symptom, which sometimes means that medications can help. Cramping in the digestive tract is treated with antispasmodic medications, for instance. In some cases of IBS anti-depressant drugs, such as fluoxetine and amitriptyline can be given. There is some concern about the pregnancy safety of these two drugs, but the jury is still out. Another drug, called loperamide, is given for diarrhea and is very safe for the fetus, since it is not absorbed from the intestines into the bloodstream, meaning that it cannot ever reach the fetus. In contrast, there is concern about a different anti-diarrheal drug called alosetron, whereas safety of another drug called eluxadoline is largely unstudied in pregnancy. Finally, there are laxatives used for IBS, particularly a type of laxative called an osmotic laxative. These work by drawing water into fiber to add bulk to stool, which helps both against diarrhea and constipation. Theses laxatives are fairly safe. As for breastfeeding loperamide and osmotic laxatives are quite safe.

Dietary strategies for managing IBS are also very important. These include adequate intake of fiber and fluids, assessment of the effects of spicy or fatty food (with reduction of these foods if helpful), and reductions of caffeine and alcohol. A diet low in FODMAPs also should be attempted for minimum of 3–4 weeks under dietitian guidance. A low, or no, lactose diet also should be attempted. With the dietary approaches, it is basically trial and error. Certain approaches work for some people and not others. Finally, regular aerobic exercise has been shown to improve IBS symptoms, plus there are psychological therapies that can be helpful.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

Leave a Reply