kidney stone in pregnancy

Overview

A kidney stone is a hard, pebble-like piece that forms in the urine inside the kidney. When it happens during pregnancy, it is called a kidney stone in pregnancy. Many stones pass out of the body on their own, but they can cause severe pain and sometimes need medical care.

It is not very common. It affects roughly 1 in 200 to 1 in 500 pregnancies.

Pregnant women, most often during the second or third trimester. Women who have had a kidney stone before, or who have a family history of kidney stones, are more likely to have one.

Symptoms

Common symptoms

• Sudden, severe pain in the side or back, just under the ribs
• Pain that spreads to the lower belly or groin
• Pain that comes and goes in waves
• Blood in the urine, which can look pink, red, or brown
• Pain or burning when urinating
• Feeling sick or being sick
• Needing to urinate more often than usual

Symptoms in children

• This article is about pregnancy, but in children kidney stones may cause belly pain rather than back pain.
• Blood in the urine
• Pain or burning while urinating
• Needing to urinate often

Symptoms in older adults

• Older adults may have less typical pain and may feel confused or very tired.
• A fever, nausea, or general weakness can be the main sign.
• Pain in the side or back may be mild or absent.

Causes

Main causes

• Pregnancy hormones slow the flow of urine, so urine stays in the kidney longer and crystals have time to form.
• The body absorbs more calcium during pregnancy, and extra calcium in the urine can help stones form.
• Levels of substances that normally stop stones from forming are lower in pregnancy.
• Not drinking enough fluids makes urine more concentrated and can also contribute.

Risk factors

• Having had a kidney stone before
• A family history of kidney stones
• Not drinking enough water
• A diet that is very high in salt or animal protein
• Urinary tract infections
• Certain medical conditions that change calcium or acid levels in the body
• Structural problems in the kidney or urinary tract

When to see a doctor

See a doctor urgently if:

• See a doctor the same day if you have severe or worsening pain, fever, chills, vomiting, blood in your urine, or if you cannot pass urine.
• Contact your maternity team if you have contractions or any concern about your baby.

Book a routine appointment if:

• Tell your midwife or doctor early in pregnancy if you have had kidney stones before.
• If you pass a stone, save it if you can and bring it to your appointment. The doctor may send it for testing.

Diagnosis

The doctor will ask about your symptoms and examine you. They will usually test your urine and blood. To see the stone, an ultrasound is often used first because it is safe in pregnancy. If the ultrasound does not give a clear answer, a low-dose CT scan may be used, but only when necessary.

Tests that may be done

• Urine test to check for blood, infection, or crystals
• Blood test to check kidney function and overall health
• Ultrasound of the kidneys and bladder
• Low-dose CT scan, only if ultrasound is not enough and a stone is strongly suspected

What to expect at your appointment

You may be seen by an obstetrician and a kidney or urinary specialist. The team will check both you and your baby. They will help control pain, keep you hydrated, and treat any infection. Most kidney stones can be managed without emergency surgery.

Treatment

The main goals are to control pain, prevent dehydration, treat infection, and let the stone pass on its own. Many stones, especially small ones, pass without surgery. Your care team will choose treatments that are as safe as possible for both you and your baby.

Self-care at home

• Drink small amounts of water often, if your care team says this is okay.
• Rest and change position gently to help the stone move.
• Use a warm compress on your side or back if it eases the pain.
• Empty your bladder often and let them know if you cannot pass urine.
• Do not take any medicine during pregnancy without asking your doctor or midwife first.

Medical treatments

Doctors may give pain-relief and anti-sickness medicines that are considered safer during pregnancy. If you are dehydrated, you may receive fluids through a drip. If the stone does not pass, a specialist may place a small tube called a stent to keep urine flowing, or drain the kidney with a thin tube through the skin. These steps are temporary. Procedures to break up or remove the stone are usually delayed until after birth.

When is surgery considered?

Surgery during pregnancy is rare. It may be considered only for a stone causing a severe infection, a complete blockage, or pain that cannot be managed. In most cases, it is safer to wait until after the baby is born.

Living with this condition

With mild symptoms, you may be cared for at home. You will need rest, fluids, and close follow-up with your maternity team. They should give you clear warning signs and an urgent contact number so you know what to do if symptoms change.

Lifestyle tips

• Keep a bottle of water nearby and sip throughout the day.
• Avoid very salty foods and processed snacks.
• Continue gentle activity, like walking, if your doctor says it is safe.
• Take your prenatal vitamins as recommended.
• Ask your care team before taking extra calcium, vitamin C, or any other supplement.

Diet and exercise

Do not cut back on calcium during pregnancy unless your doctor tells you to. Your body needs calcium to build the baby's bones. Eat a balanced diet with normal amounts of calcium and aim to drink enough fluids. Gentle walking and stretching are usually fine, but check with your care team before starting any new exercise.

Mental health and emotional wellbeing

Severe pain and worry about the baby can cause anxiety and stress. It is normal to feel scared. Talk to your midwife, doctor, or a counsellor about your feelings. If you ever feel overwhelmed, reach out to your local mental health or crisis support service for help.

Prevention

Not all kidney stones can be prevented because pregnancy changes the body in ways that make stones more likely. Drinking enough fluids and eating a balanced diet may help lower the risk. If you have had stones before, ask your doctor whether a urine or blood check is useful early in pregnancy.

Screening programmes

If you have had kidney stones in the past, your doctor may suggest simple tests in early pregnancy to look for risk factors. This is not routine for everyone, but it can be helpful.

Complications

If left untreated

• A stone can block the flow of urine and damage a kidney.
• A blocked kidney can lead to a serious infection, which can make you very ill.
• Severe pain, vomiting, and dehydration can affect your body and pregnancy.
• Kidney stones have been linked with a small increased risk of preterm labor, although this is uncommon with proper care.

Long-term outlook

With good care, the outlook is very good. Most kidney stones in pregnancy pass on their own or are managed safely. You and your baby will be monitored closely. After the baby is born, the risk of problems usually drops. Your care team may offer a simple test to understand why the stone formed, which can help you prevent future stones.

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