Accidental stool leakage, medically known as fecal incontinence, can be deeply unsettling, especially at 36 weeks of pregnancy. This common symptom is a physical consequence of the immense changes occurring in the body during the third trimester. Loss of bowel control is generally a temporary condition linked to the physical demands and hormonal shifts of late pregnancy. This is a mechanical and physiological issue that typically resolves after delivery.
The Physiological Reasons for Leakage at 36 Weeks
The growing size and weight of the uterus are the primary mechanical forces contributing to the loss of bowel control in late pregnancy. By 36 weeks, the heavy uterus creates significant pressure on the pelvic floor muscles, which form a supportive sling beneath the pelvis. This downward force strains the entire pelvic floor complex, including the muscles that control the anal sphincter. When these support muscles are continuously stretched, their ability to contract effectively and maintain a tight seal is impaired.
Hormonal changes, particularly progesterone and relaxin, further compound this strain. Progesterone works to relax smooth muscles throughout the body to prevent premature uterine contractions. This relaxing effect extends to the smooth muscle of the internal anal sphincter and the intestinal tract itself. This widespread muscle relaxation slows the digestive process and makes the sphincter less effective at maintaining passive continence.
Relaxin, produced by the placenta and ovaries, functions to loosen and soften the ligaments and joints in the pelvis to prepare for childbirth. This hormonal softening extends to the pelvic tissues and structures supporting the bowel and rectum. This increased laxity decreases the structural integrity of the pelvic floor, making the anal sphincter complex susceptible to pressure-induced failure. The growing baby and uterus can also compress the pudendal nerve, which controls the anal sphincter muscles, interrupting crucial nerve signals.
Differentiating Between Common Causes and Serious Concerns
Minor leakage is a common side effect of late pregnancy pressure, but it must be distinguished from symptoms requiring immediate medical attention. Normal third-trimester incontinence often manifests as small leaks of liquid stool or gas, typically following straining or sudden movement. This passive leakage differs from the sudden onset of continuous, severe, or watery diarrhea.
The sudden onset of severe diarrhea, especially with systemic symptoms, can signal a more serious underlying issue. Warning signs that warrant an immediate call to your obstetrician include a fever of 100.4°F or higher, blood in the stool, or severe, persistent abdominal cramping. Diarrhea lasting longer than two days, or any signs of dehydration such as dark urine or dizziness, should also be reported urgently.
It can be confusing to determine if the leakage is stool, urine, or amniotic fluid in the final weeks of pregnancy. Diarrhea is often a natural part of the body’s “clearing out” process before labor, but it is not a guarantee that labor is imminent. Amniotic fluid, which leaks from the vagina, is typically clear, odorless, and may have a slightly sweet scent, often presenting as a continuous trickle. Stool leakage, by contrast, comes from the rectum and has a distinct odor and color.
Immediate Steps for Management and Relief
Managing this temporary symptom involves dietary adjustments, specific exercises, and diligent hygiene practices. Since loose stool is difficult for a weakened sphincter to contain, adjusting your diet to form firmer stool is the first step. Focus on reducing foods that irritate the bowel or cause gas and loose movements, such as excessive caffeine, spicy foods, high-fat meals, and artificial sweeteners.
Maintaining a balance of fiber and hydration is crucial for firming up bowel movements. Soluble fiber, found in foods like oats and bananas, absorbs water in the gut and adds bulk to stool, making it easier to control. Drinking plenty of water works alongside the fiber to prevent constipation, which can lead to overflow leakage of liquid stool around a blockage.
Pelvic floor exercises, commonly known as Kegels, remain the primary solution for strengthening the muscles that support continence. To target the anal sphincter complex, focus on squeezing and lifting the muscles as if trying to stop gas or a bowel movement. Performing these exercises regularly helps maintain muscle tone and nerve-muscle connection. Good hygiene is also necessary to prevent skin irritation, which is common with anal leakage. Using absorbent pads or liners and gently cleaning the area after each episode helps maintain skin integrity and comfort.
Postpartum Recovery and Long-Term Outlook
This type of anal leakage is generally a temporary condition that resolves once the baby is born. The mechanical pressure on the pelvic floor and the rectum is immediately relieved upon delivery. As pregnancy hormones, including relaxin and progesterone, return to pre-pregnancy levels, the smooth muscles and ligaments naturally regain their tone.
For many, leakage symptoms subside within the first few weeks following childbirth. The pelvic floor muscles, however, can take longer to fully recover their strength. While significant improvement is seen quickly, it can take a few weeks to several months for muscle function to be completely restored.
If leakage persists beyond six months postpartum, effective treatment is available. The standard intervention for long-term fecal incontinence is specialized pelvic floor physical therapy. A pelvic health physical therapist can perform a thorough assessment and design an individualized exercise program to retrain and strengthen the specific muscles and nerves that control continence.