It is common for individuals in late pregnancy to experience both uterine contractions and changes in their digestive function. These two symptoms, though seemingly unrelated, often appear around the same time, leading many to wonder if one causes the other. This simultaneous occurrence of contractions and looser bowel movements is a frequent topic of discussion in the final weeks of pregnancy. The connection between the two is not a direct mechanical link, but rather a shared physiological pathway as the body prepares for childbirth.
Understanding Braxton Hicks Contractions
Braxton Hicks contractions, often called “practice contractions” or “false labor,” are the uterus’s way of preparing for true labor. These contractions are the sporadic tightening and relaxing of the uterine muscle, which can begin as early as the second trimester, though they are often not noticeable until the third trimester. Unlike true labor, these contractions are irregular and do not increase in intensity or frequency over time.
A key characteristic of Braxton Hicks contractions is that they typically subside with a change in activity, such as walking around or resting, or with proper hydration. They are generally felt in the front of the abdomen and do not cause the cervix to dilate or thin. While they may play a role in softening the cervix, they are a normal part of late pregnancy and do not indicate that labor is imminent.
The Physiological Link Between Contractions and Digestive Changes
Braxton Hicks contractions themselves do not directly cause diarrhea, as they are isolated muscular events in the uterus. Instead, both the uterine activity and the digestive changes are often the result of the same underlying hormonal shifts occurring in the body toward the end of pregnancy. As the body prepares for labor, it releases specific hormones that affect smooth muscle tissue throughout the body, not just the uterus.
The primary actors in this process are compounds known as prostaglandins. Prostaglandins are hormone-like substances that help to ripen the cervix and stimulate uterine contractions. The smooth muscle of the gastrointestinal tract is also highly sensitive to prostaglandins. When these compounds increase in the body to prepare the uterus, they simultaneously stimulate the smooth muscle in the bowels, leading to increased intestinal motility. This increased speed of transit often results in looser stools or diarrhea.
Diarrhea as a Marker for Impending Labor
While Braxton Hicks contractions are not the cause of diarrhea, the appearance of diarrhea in late pregnancy is often a more reliable sign that the body is shifting toward true labor. This pre-labor diarrhea is a common phenomenon, often attributed to the significant surge of prostaglandins released in the 24 to 48 hours leading up to the onset of labor. The digestive system essentially empties itself, which some experts believe is a natural mechanism to make room for the baby’s descent.
If the diarrhea is mild, it is typically a sign that the body is preparing for the main event. The key to differentiating this from the random appearance of Braxton Hicks is to look for accompanying changes in the contractions. If the diarrhea is paired with contractions that begin to follow a regular pattern, last longer, become increasingly painful, and do not stop when you change position or rest, this suggests the onset of true labor. True labor contractions are consistently stronger and closer together, unlike the irregular nature of Braxton Hicks.
When to Seek Medical Guidance
Although mild diarrhea is a common symptom of late pregnancy and pre-labor, it can pose a risk if it leads to dehydration. Dehydration is a concern because it can sometimes trigger uterine irritability and contractions. It is important to stay well-hydrated by drinking clear fluids, broth, and water to replace lost electrolytes.
You should contact a healthcare provider if the diarrhea persists for more than 48 hours or if you experience more than six loose stools within a 24-hour period. Immediate medical attention is necessary if the diarrhea is accompanied by signs of severe dehydration, such as dizziness, lightheadedness, a dry mouth, or significantly decreased urination.
Red Flags Requiring Immediate Care
Other red flags include a fever over 101°F, blood or pus in the stool, or severe, sharp abdominal pain that does not align with typical contractions.