What are kidney stones during pregnancy?
Kidney stones, also known as renal calculi and nephrolithiasis, are hard masses of crystal that form in the urinary tract. Technically, a kidney stone or a renal calculus is a stone that is located in the kidney itself, but the ureter (the duct that carries urine from the kidney to the bladder) is a more common location for stones during pregnancy. Known as ureteric stones, stones in the ureters occur twice as often as stones in the kidneys in pregnancy, so when we talk about a kidney stone in this report, were including ureteric stones.
There are different types of stones. Calcium stones comprise most stones in the urinary system. Usually, they consist of calcium oxalate, but during pregnancy, they are more often made of calcium phosphate. Other types of stones are struvite stone, uric acid stones, and cystine stones. During pregnancy, you are at increased risk of stones, due to a variety of changes in hormones and physiology as pregnancy advances. Additionally, due to increased pressure on the bladder, which increases the urge to urinate, pregnant women often avoid drinking enough liquids, which can increase the risk of forming calcium oxalate stones as well as uric acid stones. Its not clear whether this also increases the risk of forming calcium phosphate stones, the most common pregnancy stone type, but it is still recommended that you drink adequately.
How common are kidney stones during pregnancy?
80-90 percent of stones occur during the second and third trimester. 80 percent of stones during pregnancy are calcium stones, usually calcium phosphate. The reported incidence during pregnancy varies widely from as common as 1 case per 188 pregnancies down to 1 per 4,600 pregnancies. 1 case per 1,500 pregnancies is cited commonly, but women who have given birth multiple times are at elevated risk, plus various factors can increase your likelihood of developing stones – these include high doses of vitamin D, various metabolic disorders, and bypass surgery on the intestines, all of which can increase the concentration of either calcium or oxalate in the urine. Metabolic disorders, such as renal tubular acidosis particularly, increase the risk of calcium phosphate stones, as does topiramate, an anti-seizure medication. Urinary tract infections can provoke the formation of struvite stones, while not consuming enough liquid (as frequently happens during pregnancy) as well as high protein diets can lead to uric acid stones, but also increases the risk that calcium stones will accumulate. High levels of uric acid in the blood also lead to gout, and so having gout is a risk factor for uric acid stones. Additionally, there are genetic conditions that generate uric acid stones as well as cystine stones. In the case of cysteine, which is an amino acid (one of the building blocks of proteins), the risk comes from a genetic disorder, called cystinuria, in which there is excessive excretion of cystine and certain other amino acids through the kidneys, so it accumulates in the urinary system and stones form.
How is a kidney stone during pregnancy diagnosed?
Your blood and urine will be tested to reveal levels of substances comprising stones, such as calcium and uric acid. Blood samples also will be used for tests of kidney function. Urine will be collected continuously throughout the day. If you are suspected of possibly having a genetic condition, such as cystinuria, you will be given genetic testing, as well. Doctors will order imaging of your urinary tract, which likely will consist of ultrasound scanning and magnetic resonance urography. Any stone that you pass will be analyzed in the laboratory. In some instances, you may need computerized tomography (CT) scanning, even though this exposes you and the fetus to some amount of ionizing radiation.
Do kidney stones cause problems during pregnancy?
If a stone gets stuck, causing on obstruction of the urinary tract, this results in pain in the flank, upper abdomen, or the back. Typically, the pain advances to the lower abdomen or the groin, and you also may suffer from urinary urgency/frequency, nausea and vomiting, and blood in the urine. Often, kidney stones will eventually pass through into the urine, and the situation will resolve on its own. Otherwise, you will need treatment to break up the stone. If a stone does not pass, and the condition is not treated, there is a possibility of severe complications, including an upper urinary tract infection that can damage the kidneys, an abscess (a concentrated big infection), sepsis (infection throughout the body), and various types of rupture and leaking of parts of the urinary system. Serious complications that arise from kidney stones may put you at increased risk for certain pregnancy complications, such as preeclampsia and gestational diabetes mellitus, and may increase the chances that youll need a cesarean delivery.
Do kidney stones cause problems for the baby?
Some studies have suggested associations between stones and pregnancy complications that can harm the baby, such as preeclampsia, gestational diabetes, premature rupture of membranes (water breaks too early), low birth weight, and spontaneous abortion (miscarriage), but the findings are not consistent between different studies. On the other hand, if you develop a serious complication, such as sepsis, then the baby is in danger because your life is in danger.
What to consider about taking medications when you are pregnant or breastfeeding:
- The risks to yourself and your baby if you do not treat the kidney stone
- The risks and benefits of each medication you use when you are pregnant
- The risks and benefits of each medication you use when you are breastfeeding
What should I know about using medication to treat kidney stones during pregnancy?
A drug called tamsulosin and another drug called nifedipine may be given, sometimes with corticosteroids, to help promote the passage of stones through the urine. You may also be given pain medication in the form of opioids, which, if managed and dosed carefully, are safer than non-steroidal anti-inflammatory drugs (NSAIDs), which can be harmful to the fetus during certain times in pregnancy. If you develop an infection, you will need antibiotic treatment, and there are antibiotic regimens that are considered safe for the fetus.
Who should NOT stop taking medication for kidney stones during pregnancy?
If doctors determine that medications can help you release the stone, it is wise to continue the treatment. If you are on antibiotic treatment, you must complete the course of treatment. If you have a reaction to an antibiotic, you should contact your doctor immediately. If a particular antibiotic regimen is not good for you, you can be switched to a different regimen.
What should I know about choosing a medication for my kidney stones during pregnancy?
It is important to stay in communication with your health care provider as the release of new studies over time can change the outlook on the role of specific medications during pregnancy.
You may find Pregistrys expert reports about the medications to t
reat this condition here. Additional information can also be found in the sources listed below.
What should I know about taking a medication for my kidney stone when I am breastfeeding?
Opioid pain medication often may be given safely to nursing mothers for short periods when the infant is monitored closely. Nifedipine is not recommended in nursing mothers, and there is concern surrounding the use of tamsulosin during breastfeeding. This means that, in many cases, treatment for kidney stones occurring after you deliver will not mix with nursing, so you may need to give infant formula until you have finished with your treatment.
What alternative therapies besides medications can I use to treat my kidney stones during pregnancy?
The main management strategy for kidney stones during pregnancy is expectant management, which means that you rest while doctors monitor you closely with tests of your urine and other exams, rather than giving you tamsulosin/nifedipine or other treatments aimed at dislodging the stone. Expectant management can include pain medication plus administration of fluids. Generally, you need to drink plenty of fluids and limit intake of caffeine, whether you have a kidney stone, or to help prevent stone formation. In cases when stones do not pass, there are procedures available, such as breakup and removal of a stone through an instrument called a ureteroscope into the bladder and kidney to remove or break up a stone. The standard procedure for treating stones in non-pregnant people, extracorporeal shockwave lithotripsy (ESWL), is contraindicated in pregnancy. However, another procedure, called laser lithotripsy, appears to be safe and effective in pregnancy, particularly for ureteral stones.
What can I do for myself and my baby when I have a kidney stone during pregnancy?
Follow the instructions of your physician and report any medication side effects to your physician.
Resources for kidney stones in pregnancy:
For more information about kidney stones during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or contact the following organizations: