A bladder blockage (obstruction), also known as a lower urinary tract obstruction (LUTO), is a rare fetal condition diagnosed during a prenatal ultrasound. It is a birth defect where the fetus’ urine flow is blocked and the bladder is unable to empty. LUTO can cause damage to the baby’s developing organs leading to severe health problems.
About the urinary tract and LUTO
The urinary tract is made up of two kidneys which drain urine through tubes that connect to the bladder called ureters. The bladder holds urine until it is full, then it empties through the urethra out of the body. During pregnancy, this urine becomes the amniotic fluid within the womb surrounding the baby. It helps cushion and protect the baby. The baby practices swallowing and breathing while they receive oxygen and nutrition needed through the umbilical cord. Amniotic fluid not only helps cushion the baby in the womb, but most importantly, helps the baby’s organs develop before birth.
When LUTO is present, there is a blockage at the bladder or urethra that does not allow all the urine to drain out of the bladder. This makes the bladder full of urine and enlarged. When the urine cannot flow out, it can back up into the ureters and kidneys. This can cause damage to the kidneys and how they function. This may cause abnormalities in kidney development, including kidney cysts. It can also cause dilation or swelling in the kidneys and ureters known as urinary tract dilation or hydronephrosis.
The blockage of urine flow can cause low amniotic fluid levels around the baby. Low amniotic fluid is known as oligohydramnios. If amniotic fluid is very low or does not exist this is known as anhydramnios. If the baby does not have enough amniotic fluid around them, it can cause poor development. This damage may cause severe lung and breathing problems after birth. If a pregnancy is complicated by anhydramnios, the impact can be severe and life-limiting even with intensive care after birth.
As soon as a baby is delivered, our primary concern is how well they can breathe on their own. Babies with breathing problems may be placed on a ventilator until their lungs develop better and they can breathe on their own. Once their breathing issues are controlled, a team of specialists will evaluate and treat the urinary obstruction.
Evaluation and diagnosis
Before your baby is born, the Fetal Center will evaluate your baby’s condition. Your doctor may order additional tests to help get more information, such as:
- Prenatal ultrasound
- Fetal MRI
- Fetal echocardiogram
- Fetal urine testing, called a vesicocentesis
The most common conditions causing LUTO are:
- Posterior urethral valves – a flap of tissue blocking the urethra
- Urethral atresia – a complete or near complete blockage of the urethra, meaning no urine can get out of the bladder
- Prune Belly syndrome also known as Triad syndrome or Eagle-Barrett syndrome – narrowing of the urethra making it difficult for urine to leave the body
If your baby is found to have LUTO, the Fetal Center may schedule a prenatal consultation with a maternal-fetal medicine specialist, neonatologist, fetal radiologist, pediatric urologist and pediatric nephrologist to learn more. These specialists will help you learn more about your baby’s condition, treatment options and care before and after birth.
Monitoring LUTO during pregnancy
During your pregnancy, you may have regularly scheduled ultrasounds to check amniotic fluid levels and your baby’s condition. If your baby appears to have LUTO but has normal amniotic fluid levels, your doctor will continue to monitor closely. If the amniotic fluid levels are low, your doctor may recommend a procedure to help the fluid drain out of the bladder.
Treatment for LUTO
Treatment for LUTO
For patients with severe oligohydramnios or anhydramnios, treatment for LUTO may begin with fetal surgery during pregnancy while the fetus is still in the womb.
In babies with LUTO, the Fetal Center may use a vesicoamniotic shunt. This tube will help the fluid (urine) move from inside of your baby out to the amniotic fluid surrounding them.
A vesicoamniotic shunt is a small, flexible, plastic tube that is placed in your baby’s abdomen (belly) during pregnancy. One end of the shunt (tube) goes into the baby’s bladder and the other end remains in the amniotic fluid in the uterus. The tube will help the fluid (urine) move from inside of your baby’s bladder out to the amniotic fluid surrounding them. This will help add to the amniotic fluid levels. If additional amniotic fluid is needed, the doctor may infuse saline into the womb during the same procedure. The shunt will remain in place until after the baby is born.
Delivering with LUTO
For the remainder of your pregnancy, you will have regularly scheduled ultrasounds to check the amniotic fluid levels and your baby’s condition. If fetal surgery to place a shunt is necessary, you may be able to receive ongoing pregnancy care at your local doctor. The Fetal Center will remain in close contact with your doctor to follow your health, address any issues or questions and provide care as needed.
If your baby has had vesicoamniotic shunt placed, it will not affect how you decide to deliver your baby. You can choose a vaginal delivery as long as there are no severe fetal or maternal conditions that impact the decision. Due to the need for specialized care for your baby after birth, your baby will be born in the Riley Maternity Tower where our team of specialists will be ready to care for you and your baby.
Following delivery, your baby will be cared for in the Neonatal Intensive Care Unit (NICU). If needed, your baby will have the most comprehensive Level IV neonatal care and specialty services available. This ensures that you and your baby can stay together after delivery.
While in the NICU, the team including neonatologists, pediatric urologists and pediatric nephrologists will carefully monitor your baby’s breathing and kidney function. Some babies with LUTO need respiratory support to breathe including a ventilator.
Your baby’s length of stay in the hospital may depend on how their lungs have been impacted by the low amniotic fluid level during pregnancy. Your doctors can discuss this and any questions you may have before delivery.
After delivery and once your baby’s breathing has been stabilized, your child’s doctors may run additional tests to have a clear diagnosis. These tests may include:
- Renal ultrasound. This test looks at the kidneys’ development and assesses the bladder’s shape and degree of thickness and how full or distended it is. The degree of kidney and ureter dilation or swelling is also assessed.
- Blood tests. Your child's doctor will perform a blood test to measure kidney function and see how well infants excrete creatinine (a waste product). Electrolyte levels in the blood are also tested.
- Voiding cystourethrogram (VCUG). In this test, contrast dye is injected into a bladder catheter and allows the doctor to see any vesicoureteral reflux—the amount of urine that backs up into the kidneys. It will also show whether there is blockage of the urethra. This test provides the most definitive diagnosis of PUV in infants.
- Renal scan. These are medicine tests called dimercaptosuccinic acid (DMSA) or mercaptoacetyltriglycine-3 (MAG-3) scans that allows your child’s doctor to see his or her kidneys and learn more about how they are functioning. DMSA looks at kidney function, shape and whether scarring is present. MAG-3 Lasix scan looks at kidney function, shape and position as well as how well they drain.
- Urodynamic studies. These assess how the bladder empties and stores urine. This evaluates the pressures in the bladder and helps to the urologist to understand how the bladder has been affected by LUTO. This test is often performed later in infancy.
Future pregnancies: Having a fetal vesicoamniotic shunt placed should not impact your future pregnancies.
Key Points to Remember
Key Points to Remember
- A lower urinary tract infection or LUTO is a birth defect where the baby’s urine flow is blocked and the bladder is unable to empty.
- LUTO can cause damage to the baby’s developing organs leading to severe health problems.
- If your baby is found to have LUTO, the Fetal Center may schedule a prenatal consultation with a maternal-fetal medicine specialist, neonatologist, fetal radiologist, pediatric urologist and pediatric nephrologist to learn more.
- In babies with LUTO, the Fetal Center may use a vesicoamniotic shunt. This tube will help the fluid (urine) move from inside of your baby out to the amniotic fluid surrounding them.
- After delivery and once your baby’s breathing has been stabilized, your child’s doctors may run additional tests to have a clear diagnosis.
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