The reasons for frequent urination during pregnancy are many. One of them is the normal pressure exerted by the growing uterus on the bladder. However, there are also some pathological reasons that need to be taken into consideration.
First, let's understand the non-pathological reasons for frequent urination during pregnancy.
The bladder is located in front of the uterus. At 3 months of pregnancy, the uterus enlarges and moves out of the pelvic cavity, and the enlarged uterus can be felt above the pubic symphysis. At this time, the enlarged uterus can stimulate the bladder in front of it, leading to frequent urination. In the middle stage of pregnancy, the uterus gradually enlarges within the abdominal cavity, reducing the stimulation on the bladder. After 28 weeks of pregnancy, irregular uterine contractions (uterine hardening) can occur without symptoms. However, if contractions stimulate the bladder, frequent urination can occur. If contractions are frequent and occur before full term, prompt medical attention is necessary to prevent premature birth.
In the later stages of pregnancy, around 38 weeks, the fetal head descends into the pelvis, which can also compress the bladder and cause frequent urination. During the day, when expectant mothers are standing or sitting, the enlarged uterus can compress the large blood vessels in the abdomen, causing impaired venous return in the lower limbs and reduced kidney blood flow, resulting in decreased urine output. When lying down at night, the pressure of the uterus on the inferior vena cava is relieved, increasing kidney blood flow and leading to increased nighttime urination. This is a normal physiological phenomenon of pregnancy. However, if accompanied by polydipsia, polydipsia, polyuria (the "Three Poly Symptoms") and no weight gain, prompt medical attention is needed to rule out the possibility of gestational diabetes.
In addition to the above reasons, frequent urination during pregnancy can also be caused by certain diseases. If the following signs of illness occur, expectant mothers should seek medical attention promptly.
1. Urinary tract infection (UTI)
Although it is normal for many expectant mothers to experience frequent urination at the beginning of pregnancy, pathological signs should not be ignored. After pregnancy, due to the displacement of the ureters and bladder, urine can accumulate in the urinary tract, making it easier for bacteria to multiply and leading to urinary tract infections. If there is pain during urination or unbearable urgency, a urinalysis can be performed to check for urinary system infections. The period of 4 to 12 weeks of pregnancy is a sensitive period for fetal malformation. Medication should be used cautiously under the guidance of a doctor, but not absolutely prohibited. Increasing fluid intake, frequent urination, bladder and urethral irrigation can help reduce bacterial retention in the urinary system, and appropriate use of antibiotics can alleviate symptoms as soon as possible.
2. Cystitis
In addition, frequent urination may also be caused by other factors, such as inflammation. When there is inflammation in the bladder, the threshold for nerve sensation decreases, and the urinary center is in an excited state, resulting in frequent urination unrelated to inflammation. Urinary tract stones and foreign bodies usually manifest with frequent urination as the main symptom. Reduced bladder capacity, such as bladder space-occupying lesions, tuberculous bladder contraction, or large bladder stones. Psychogenic frequent urination, which is only seen during the day or before bedtime at night, often occurs in individuals under mental stress or in patients with hysteria, and may be accompanied by urgency and pain. If frequent urination is accompanied by urgency and pain, prompt medical attention is necessary.
In the first three months of pregnancy, as the uterus gradually enlarges within the pelvic cavity, it presses on the bladder, causing constant urination for expectant mothers. In the middle stage of pregnancy, the uterus rises to the abdominal cavity, and the symptoms of frequent urination improve. However, frequent urination may reoccur in the latter stages of pregnancy. If frequent urination occurs and the amount of urine each time is not much (excluding urinary tract infections), it is due to the aforementioned reasons. If frequent urination is accompanied by a large volume of urine, caution should be taken for conditions such as diabetes, and further examination should be conducted at a hospital. When feeling the need to urinate, expectant mothers can go to the restroom more frequently without worry, and they should try not to hold their urine. If there are abnormal symptoms such as pain or burning during urination, immediate medical attention should be sought.
