What Causes Kidney Stones in Pregnancy

Kidney Stones in Pregnancy – Causes

Proper kidney functioning is vital for a person to remain healthy for a lifetime.  The main functions of the kidneys are to separate toxins, mineral salts and other waste materials from the blood; to regulate water fluid levels within the body’s system, and to secrete urine.

Kidneys are a pair of organs situated just below the ribcage on either side of the spinal column.  Each kidney contains innumerable tiny excretory units called nephrons which filter the blood as it passes through, separating water fluids and waste products from it.  Most of the water is returned back to the blood while enough is used to make urine.

Urine secreted by kidneys contain many chemical elements that combine together to form mineral salts.  These are soluble in a solution and the proportion of water is normally high in urine.  Thus, most mineral salts are dissolved before being discharged out of the body along with urine.  But, when the concentration of mineral salts is high in urine and comparatively less in water, the salts will begin forming into crystals and later develop into a solid mass called kidney stone.


As it is, the body requires ample amounts of water to carry on with its normal functions as well as to produce enough urine.  Since urine is discharged frequently, the water supply should be constant to be able to produce dilute urine.  This water requirement is doubled during pregnancy.  A conscious effort should be made to meet the body’s water needs, and when a pregnant lady fails to make this effort diligently, she will be at an increased risk of developing kidney stones.  Less urine volume means more concentrated urine and slow drainage, for the urge to urinate arises only when the bladder is full.  Urine accumulated for an extended period of time makes it easier for crystals to form and collect together to grow into a solid kidney stone.

There are several changes occurring in the body of a pregnant woman, some of which can increase their risk of developing kidney stones.  While pregnant, the kidneys increase their filtering process, thus doubling the amount of waste mineral salts in the urine.  If water intake is not adequate, crystallization of mineral salts and their further growth into kidney stones becomes inevitable.  So during pregnancy, whenever thirst needs to be satisfied, drink plenty of water instead of taking in carbonated, caffeinated, or carbonated beverages.  The above mentioned have an increased tendency of dehydrating the body even more.

During pregnancy, it is recommended that calcium intake be increased to prevent any growth defects in the fetus.  So even while a high calcium diet is followed, calcium and vitamin D supplements are prescribed to strengthen the expectant mothers’ bones as well as the fetus.  This leads to enough calcium reserves, more than what is required by the fetus, and this increases the woman’s risk of forming calcium based kidney stones.

Another factor, contributing to the formation of kidney stones during pregnancy, is the compression occurring in the ureters and kidneys from the growing uterus.  This can cause urinary obstruction.  While the entire urine produced fails to be discharged in totality, retained urine that begins to accumulate provides the perfect environment for mineral salt crystallization and kidney stone formation.