Pregnancy brings about many physical transformations, including changes in digestion and the perception of odors. It is common for pregnant individuals to notice that their feces seem to smell different or much stronger than before. This phenomenon is a validated side effect of the significant physiological adjustments occurring in the body.
Is This Change Normal During Pregnancy
A change in fecal odor during pregnancy is a common and generally harmless occurrence. This altered perception results from two distinct physiological changes happening simultaneously. The digestive process is altered, which changes the composition and intrinsic smell of the stool.
Many pregnant people experience a heightened sense of smell, known as hyperosmia, particularly in the first trimester. This increased sensitivity means that existing odors, including those from bowel movements, can be perceived as much more intense or even repulsive. About two-thirds of pregnant women report this increased olfactory sensitivity.
Hormonal and Digestive Mechanisms
The underlying physiological reason for the change in stool characteristics is primarily hormonal, specifically the elevated levels of progesterone. Progesterone causes the smooth muscles throughout the body to relax, including those in the walls of the gastrointestinal tract. This relaxation slows down peristalsis, the wave-like muscle contractions that move food and waste through the intestines. The resulting slower transit time means that waste material spends a longer period in the colon. This extended stay allows the bacteria in the gut more time to ferment the waste, which alters the composition of gases and compounds that contribute to the fecal odor, making it more pungent.
The composition of the stool is further modified by common changes in diet and supplement intake during pregnancy. Many pregnant individuals experience shifts in appetite, developing intense cravings or strong aversions to certain foods. These dietary changes, coupled with the need for prenatal vitamins, especially those containing iron, can drastically impact the gut flora and waste composition. Iron supplements are a well-known cause of constipation and can also cause stools to turn a dark green or black color, which may be accompanied by a change in smell.
Identifying Warning Signs
While most changes in fecal odor and consistency are a benign result of pregnancy hormones, certain accompanying symptoms warrant a call to a healthcare provider. A sudden and persistent change, especially if accompanied by severe digestive distress, may signal an issue that requires attention.
One of the clearest red flags is the presence of blood or mucus in the stool, which should always be reported to a doctor. Stool that is excessively pale, white, or clay-colored, or that appears greasy or floats frequently, could indicate a problem with fat malabsorption or issues with bile flow from the liver.
Additionally, severe diarrhea that lasts longer than 24 to 48 hours, or is accompanied by fever, persistent vomiting, or signs of dehydration, should be addressed immediately. Any accompanying severe abdominal pain, unexplained weight loss, or a sense of not feeling the baby move as much should prompt an urgent medical consultation.