Kidney Stones During Pregnancy

Along with the other challenges faced by women while they are pregnant, you can add the risk of developing a kidney stone.

The risk of stone formation during pregnancy.

A woman’s physiology changes dramatically during pregnancy, which can influence her chances of developing a new stone. While some changes increase a woman’s likelihood of forming a new stone, others decrease it. The end result is that the rate of stone formation during pregnancy actually appears similar to the rate in non-pregnant women and has been estimated to occur in 1 in 1500 pregnancies.

Changes during pregnancy that have an effect on stone formation:

  • A woman’s cardiovascular system increases it output.
  • Her kidneys increases their filtration activity.
  • More calcium is absorbed by the intestines and more is released into the urine.
  • Other urinary substances also increase including citrate, which helps prevent stones.
  • The upper urinary tract (including kidneys and ureters) become dilated due to compression from the uterus and the effects of hormones. This is more pronounced on the right side and can lead to slower transport of urine and higher chances of infection or stone formation.

When do stones present during pregnancy and what are the chances of spontaneous passage?

Researchers in France have recently compared 244 pregnant women who formed stones with 5,712 non-pregnant female stone formers (Meria and coworkers). They found that stone episodes during pregnancy occurred primarily during the second and third trimesters, which accounted for 39% and 46% of the episodes. Encouragingly, 81% of the pregnant women were able to successfully spontaneously pass their stones in their group of patients, a much higher success rate than in the non-pregnant women (47%). Stones in the pregnant women were more likely to be calcium phosphate in nature rather than the more common calcium oxalate stones seen in the general population, reinforcing the fact that stone formation during pregnancy is a result of unique pregnancy related changes in physiology. More recent research published by Burgess and colleagues from Minnesota also found a high percentage of calcium phosphate stones but reported a much lower successful spontaneous passage rate of only 48%.

Diagnosis and treatment of stones during pregnancy.

The diagnosis and treatment of kidney stones during pregnancy can be more difficult because the need to limit radiation from x-rays to the growing baby makes diagnosing stones less certain and concerns about potential health risks of stone surgery when a woman is pregnant can restrict the surgical options available.

Radiation exposure from x-rays or CT scans used to diagnose a stone is more of a risk to the fetus during the first trimester. While the risk is lower during the second and third trimester, experts do not agree on whether there is a “safe” level or radiation and the philosophy of avoiding unnecessary radiation and minimizing it when it is unavoidable is advisable. This strategy includes using ultrasound or MRI initially to establish a diagnosis. However, these studies are not as accurate as CT for the diagnosis of stones. Because an undiagnosed stone can carry its own risks to the mother and fetus (pain, infection, preterm labor, and hypertension), in certain cases, the risk of obtaining imaging in order to treat a stone may be justified. Low dose CT scan protocols or plain x-rays may be used in these situations to still limit the amount of radiation exposure.

Once a stone is diagnosed, the decision to treat or observe it depends on factors such as whether pain is uncontrolled, infection is present, or kidney function is impaired. When these conditions are not present, a trial of passage or observation with planned treatment after delivery should be considered first because half or more of these stones will pass spontaneously. If intervention is needed, the options include placement of a ureteral stent or nephrostomy tube. If a stent is chosen, it may need to be changed every 2 months or more frequently because of the faster development of stent encrustation (stone particles forming on a stent) that occurs in pregnant women. A nephrostomy tube, placed through the skin directly into the kidney, avoids this issue but is associated with the inconvenience of requiring an external drainage bag. Treatment during pregnancy is usually limited to ureteroscopy with laser lithotripsy. Shockwave lithotripsy is not performed because of risks from the shockwaves on the developing fetus and percutaneous nephrolithotripsy is avoided because of the belly down position necessary for surgery. Both procedures also require a moderate amount of undesirable x-rays.

Steps you can take.

The most important step you can take to help prevent the development of a kidney stone while you are pregnant is to keep your water intake high. This will make your urine more dilute and make it less likely a new stone will form.

It is important to seek professional evaluation and care if you think you may be suffering from a stone. Typical symptoms of a stone during pregnancy include nausea, vomiting, blood in the urine, and flank or abdominal pain.


Thomas et al, “Urologic emergencies during pregnancy.” Urology, 2010.

Meria et al, “Stone formation and pregnancy: pathophysiological insights gained from morphoconstitutional stone analysis.” Journal of Urology, 2010.

Burgess et al. “Diagnosis of Urolithiasis and Rate of Spontaneous Passage During Pregnancy.” Journal of Urology, 2011.


About Dr. Mike Nguyen

Mike M Nguyen, MD, MPH, is a urologist and an Associate Professor of Clinical Urology at the Keck School of Medicine of USC in Los Angeles, CA. He specializes in the treatment of kidney stones with both surgery and dietary prevention and the in the treatment of kidney and prostate cancer using the latest robotic surgical approaches. He sees patients at clinics located in Los Angeles, Pasadena, and La Canada, CA. He is the founder of the website.
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77 Responses to Kidney Stones During Pregnancy

  1. Melissa says:

    I had kidney stones with my second baby had a stent put in shortly after giving birth and just before my operation 8 months later I found out I was pregnant again now in such severe pain and wondering if anyone else has gone through this and what doctors done to help as it seems I have no options

  2. Krystin Franklin says:

    I have had multiple kidney stones during this pregnancy. It is my first time being pregnant and ever having stones in my life. It is horribly painful. I am now 38 weeks along. During the second trimester doctors gave me a prescription pain killer but now being so close to my due date idk what to do. Im miserable and havent slept in days. I have noticed different positions cause more pain. What position do you think is the best to lay in? What things have helped you or do you know of?

  3. Xoliswa buthelezi says:

    I’m 5 months preg and I just have a kidney stone on my rights side,what can I do to protect my baby?

  4. lebo says:

    I have a pain when I have sex and my bloodier becomes full each and every second.

  5. E in California says:

    I am 39 wks pregnant with my 7th child and have been having flank pain on both right and left sides with nausea and vomiting. While I was pregnant with my 2nd child I was told I have Gallstones but was later told after child 6 that it was just sludge. I have had several UTIs early on in this pregnancy but have never felt this amount of pain since I was first told I have gallstones/sludge. Please advise. My due date is April 29, 2017 and my next OB check is not until April 25th. I am in so much pain I can not sleep and I feel like I have to urinate every 5 mins.

  6. Verity says:

    I’m 12 weeks pregnant and got a kidney stone that is 1 cm big the paint is unreal when I go to toliet I’m losing so much blood in urine .. Iv had infection
    For the whole 12 weeks don’t feel great would be safe to have an op
    Please is any one got advice

    • jay says:

      I am 30 weeks pregnant and have had a stent placed for the past week and a half and it is the most uncomfortable thing that I have ever had to go through. My stone is 9mm and wont pass with this stent. The stent is supposed to be removed in 4 weeks and replaced and then stay put until after the baby is born in the beginning of June. After recovering from delivery then they will go back in and get rid of the stone. If I could do it over again I would rather go back to the sporadic blood in my urine and temporary pain, because with this stent I have had blood in my urine everyday and the “uncomfortable” pain associated with the stent has not gone away yet. Best of luck to you! I hope you can avoid getting a stent especially at 12 weeks!!

  7. sultan hasan says:

    my wife is 7 week pregnant and she had 5.6mm kidney stone at her right side kidney and doctor advice her as she drink enough water but she can’t drink water well.when she drink it vomit her.what her solution?

  8. Cy says:

    I am 23 yrs old and i have 0.3 sand in my kidney and i have uti,,its affect for me to pregnant?

  9. Andrea Tufaro says:

    I am trying to get pregnant but i have a kidney stint in.. Will the kidney stint provent me from getting pregnant??

  10. Kristen says:

    I’m currently 28 weeks pregnant and went to the er last night after 2 days of excruciating pain. I thought a uti or kidney infection and explained my pain to the staff (they wheeled me to labor & delivery immediately) I described my symptoms; intense pressure on my bladder, frequent (every 30 min) urination, barely any pee coming out but horrible pain and burning at the end of every stream, excruciating pain on the left side of my back, then random bursts of shaking chills, full body pain and vomiting. The hospital checked that the baby was okay, asked how bad the pain was, checked my urine (I was dehydrated, found blood in urine and high white and red blood cell count + high blood pressure) I waited 30 min for the doctor who never came in finally the nurse says: “doctor said it sounds like kidney stones. Take Tylenol, plenty of water and a hot compress for pain. I was never seen by a doctor and they didn’t check anything except my urine. I was crying in pain while walking back to the car because they didn’t offer a wheel chair again. I’m terrified, can’t sleep, feel like I’ve never ever felt before and I don’t know what to do. Advice please, anyone!

    • Kristen says:

      *correction, pain was on the right side of my back!

      • Michelle says:

        Sounds like a bladder to kidney infection. Hope you’ve seen your regular doc since then and are ok. Completely negligent of the ED. Did they do an U/S or MRI?

        Best of luck,

        A nurse somewhere

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  13. Amber says:

    I passed seven kidney stones while pregnant with my daughter. Two in my first trimester and five in my third trimester. An ultrasound done in my seventh month of pregnancy showed a few stones in my right kidney and several in my left. Before getting pregnant, I had already had 15 years of experience with stones. My first stone was discovered when I was 14.

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  15. Sulochana chettri says:

    I m suffering from stone n bad pain and also I m pragnent so what should I did operation due to this I’m suffering badly pain do what should I do …..I’m confused

  16. athisha says:

    I’m in 17 weeks pregnancy my age is 23 tdy morning I have a pain at stomach I doubted I’m attacked the kidney stones very sad and fear pls reply

  17. nayana says:

    Please Doctor advise me I m 10 week pregnant I have kidney stone pain I was admitted in hospital im taking tablets as given by doctor is it any problem for my baby
    also I have urine infection please doctor advise me im worried.

  18. Laura Oliveros says:

    Hi, I’m currently pregnant I’m about 25 weeks. I’m struggling with kidney stones.
    I have so much pain on my left flank. I’m taking “Narco” for pain. The medication works it takes my pain away. I would like to know if that is safe for the baby. Doctors tell me it is but I have my doubts and am scared every time I take it.

  19. Diane ross says:

    I have just found out i am pregrant and i suffer from kiddney stones and would like some information on what i can take and how this effects my baby thank u can u plz get back too asp as i am very worried

  20. Anya MacTavish says:

    need info on kidney stones for young mother emailed to me @

    • Chetna Sharma says:

      I have just found out i am pregrant completed five month and i suffer from left kiddney stones and right kiddney stones size 4mm and one stone in gallblader would like some information on what i can take and how this effects my baby thank u can u plz get back too asp as i am very worried

  21. vera onyeche says:

    Pls Dr,I was diagnosed of hyperthyroidsm,now am pregnant jst five weeks a severe pain developed which is said to be kidney stone.pls wat can I do idnt want to loose my pregnancy and the complications on me.though I have been placed on anti biotics so dt the painful symtoms can stop.thank u

  22. Cassie says:

    I am 15 weeks pregnant and just wanted to put my story out there. No doctor I’ve had has believed me, so obviously I have no answers. I have chronic kidney stones, normally and my left kidney is deformed due to surgery and always has at least a few stones in it all the time. I pass about 15 stones per year and need surgery to remove the larger ones about every 2 years. Anyway, I have had two successful pregnancies and and I am on my third right now. Every time I am pregnant, my stones dissolve to the point of becoming sand. So instead of passing stones, I am peeing sand, which you’d think wouldn’t be painful, but it is just as painful as passing small 1-2mm stones(which is relative, because I’m used to it). I have had kidney pain for the last two weeks and I have noticed “exit” pain at least 7 times in the last month, without noticing a stone coming out, but now I’ve had a closer look and I am seeing sand again. Anyway, my real question is: are there changes in acidity/alkalinity, citrate levels, what is it that changes during pregnancy that is dissolving my kidney full of stones? If I had an idea, maybe I could make a change post-pregnancy to keep the stones at bay or at least keep them from getting to 7mm and having to pass them or go to the hospital. If anyone can even refer me to someone who has more information, it would be greatly appreciated. Thank you for your time!

    • Megan says:

      Acid is good for desolving the stones…. I am 27weeks pregnant and am passing stones now. If you drink water with lemon in it that is the best thing to help you…. Your body absorbes more calcium while you’re pregnant which causes the stones to for… I get them quite often! Hope this helps you a bit

    • Amber says:

      My stones also changed in composition during pregnancy. If you pinched them after they came out( they were not hard, but soft formed),they would separate into sand between my fingers. I never got any answers to my questions about this, when I asked my obgyn or my urologist. I always thought that I was producing stones at such a fast rate, that they didn’t have time to fully solidify.

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