Kidney stones are hard deposits of minerals and salts that form inside the kidneys. While they can affect anyone, their development during pregnancy warrants special attention to ensure the well-being of both the mother and the developing fetus. These stones can range in size from a small grain of sand to something much larger.
Causes and Symptoms of Gestational Kidney Stones
Pregnancy brings about physiological shifts that can promote kidney stone formation. An increase in the hormone progesterone causes the smooth muscles of the urinary tract to relax, which can slow the flow of urine. This urinary stasis allows more time for minerals to crystallize and form stones. Additionally, a pregnant person’s body increases calcium excretion into the urine, particularly in the second and third trimesters, which can contribute to calcium-based stones.
The growing uterus also plays a mechanical role by compressing the ureters, the tubes that carry urine from the kidneys to the bladder. This pressure can impede urine flow, further increasing the risk of stone development.
Common symptoms of kidney stones during pregnancy can mimic some normal discomforts, making them tricky to identify. A primary indicator is a sharp, intense pain in the back, side, or lower abdomen that may come in waves. This pain can also radiate towards the groin. Other signs include blood in the urine, known as hematuria, nausea, vomiting, and a more frequent or urgent need to urinate. Because some of these symptoms overlap with other pregnancy-related issues, reporting severe or persistent pain to a healthcare provider is necessary for a proper diagnosis.
Safe Diagnostic Procedures
Diagnosing kidney stones in pregnancy is approached with caution to protect the fetus. The primary diagnostic tool is a renal ultrasound. This procedure is safe as it uses sound waves, not radiation, to create images of the kidneys and urinary tract. An ultrasound can effectively identify the presence of a stone and reveal if the kidney is swollen due to a blockage, a condition known as hydronephrosis.
A urinalysis is also a common diagnostic step, used to check for the presence of blood, crystals, or signs of infection in the urine. Blood tests may also be performed to assess kidney function and check for indicators of infection.
In infrequent and more complex situations where an ultrasound does not provide a clear diagnosis, a physician might consider a low-dose computed tomography (CT) scan. This is reserved for cases where the potential benefits of a definitive diagnosis are determined to outweigh the minimal risks associated with the low level of radiation exposure.
Managing and Treating Kidney Stones
The approach to managing kidney stones during pregnancy is conservative at first. For most small stones, the primary treatment involves increasing fluid intake. Drinking plenty of water helps to dilute the urine and can assist in flushing the stone out naturally. Pain management is also a focus, using medications, such as acetaminophen, that are generally considered safe for use during pregnancy. This watchful waiting approach is often successful for stones that are not causing severe symptoms or blockage.
When a stone is too large to pass on its own, causes unmanageable pain, or creates a significant obstruction to urine flow, procedural intervention becomes necessary. One common and safe procedure is a ureteroscopy. This involves inserting a very thin, flexible scope through the urethra and bladder and up into the ureter to either remove the stone directly or break it into smaller, passable pieces using a laser.
Another option for relieving a blockage is the placement of a ureteral stent. This is a small, temporary tube inserted into the ureter to bypass the stone, allowing urine to drain freely from the kidney to the bladder. The stent remains in place until the stone can be addressed more definitively, often after delivery.
Associated Risks and Prevention Strategies
Untreated kidney stones during pregnancy can lead to several complications. They can increase the risk of recurrent urinary tract infections (UTIs) and potentially lead to a more serious kidney infection called pyelonephritis. There is also evidence suggesting a possible link between symptomatic kidney stones and an increased risk of preterm labor.
Preventing kidney stones is a part of a healthier pregnancy. The most effective preventative measure is maintaining adequate hydration. Drinking plenty of water throughout the day dilutes the substances in urine that lead to stone formation. Aiming for about ten 10-ounce glasses of fluid daily is a common recommendation, though this can vary.
Dietary choices also play a role in prevention. It is often advised to moderate sodium intake, as high levels can increase calcium in the urine. For those prone to forming calcium oxalate stones, a doctor might suggest discussing whether to limit foods high in oxalates, such as spinach and nuts.