Skip to Document Content

Lower Urinary Tract Obstruction (LUTO)

Lower Urinary Tract Obstruction (formerly referred to as Fetal Bladder Outlet Obstruction) is a blockage in a baby’s bladder that restricts or prevents most or all of the flow of urine out of the body. It varies in severity from mild, requiring minimal treatment after birth, to very severe, causing serious kidney problems and requiring surgery.

It is important to note that LUTO is not related to anything a mother did or did not do during pregnancy. It is typically a result of one of the following:

  • In most boys with this condition there is a thin membrane, a posterior urethral valve, which blocks the urine.
  • In rare cases, the urethra has not formed properly, and the urine cannot exit the body, a condition known as urethral atresia. This affects both boys and girls.

If your baby has been diagnosed with LUTO, we understand the worry and anxiety you may have. Our dedicated team of specialists at the SSM Health Cardinal Glennon St. Louis Fetal Care Institute are uniquely equipped to help you and your baby. Working with a multidisciplinary team, we comprehensively monitor and treat this condition, using the safest techniques to treat your child before or after delivery.

comparing a healthy baby and a baby with BOO
This graphic shows a baby with BOO. The bladder is obstructed which restricts the flow of urine enlarging the kidneys.

How Is It Diagnosed?

LUTO can be diagnosed as early as 14 to 16 weeks but is often found during a focused ultrasound at 20 to 24 weeks of gestation. In analyzing the ultrasound, the dedicated and multidisciplinary team of physicians at the Cardinal Glennon St. Louis Fetal Care Institute will look at the size of the fetal bladder and developing kidneys, and the amount of amniotic fluid to determine whether there is an obstruction and to provide an accurate diagnosis.

How Is LUTO Managed During Pregnancy?

After diagnosing LUTO, our team assesses the severity of the obstruction in order to provide the immediate care and attention your baby needs. Mild cases may only require observation during pregnancy and further evaluation after birth. However, in severe cases there are higher chances of kidney, bladder, and lung dysfunction because they are all linked in development through the amniotic fluid. In these situations, fetal surgery may be an option.

Before considering surgery, the Cardinal Glennon St. Louis Fetal Care Institute team must examine the degree of kidney damage by doing an ultrasound or a fetal urine analysis. To perform the fetal urine analysis, the surgeon places a very small needle through the mother’s abdomen and into the baby’s bladder—much like an amniocentesis, to collect a urine sample. The fetal urine is analyzed to help determine the kidney function.

Once the kidneys have been evaluated, our team will help you make the best decision for your baby, and whether fetal intervention is an option. Those most likely to benefit from fetal surgery are those with an obstruction severe enough to damage kidney and lung development, but not so severe that the kidney damage is irreversible. Fetal surgery aims to restore the flow of urine into the amniotic sac, allowing the lungs and kidneys to develop.

What Is The Surgery For LUTO And How Does It Affect The Baby After Delivery?

The most common fetal surgery option for LUTO is the placement of a vesicoamniotic shunt. The shunt is a small flexible tube that is placed through the skin and into the baby’s bladder, allowing urine to pass into the amniotic cavity. The shunt can increase the potential for normal amniotic fluid levels, which assist in the proper function and development of the fetal kidneys, bladder, and lungs.

How does LUTO affect my baby after delivery?

Shortly after delivery, your baby will require kidney ultrasounds, as well as blood and urine tests to ensure that the kidneys are functioning well. In some cases, a pediatric urologist will perform a third test called a Voiding Cystourethrogram (VCUG) to ensure that the urine is not backing up from the bladder into the kidneys.

LUTO impacts every child differently; our pediatric urology team will work with you and your family to determine the best course of care for your newborn baby.

You may have a lot of questions, and that’s okay. We’re available to help 24 hours a day, 7 days a week. For more information or to schedule an appointment, call us at 314-268-4037or toll free at 877-SSM-FETL (877-776-3385).

Patient Stories About Lower Urinary Tract Obstruction (LUTO)

dad with mom holding little boy smiling at camera

At the St. Louis Fetal Care Institute, we understand the fear and confusion that come with the diagnosis of a prenatal medical condition. We share these patient stories to offer comfort, hope, and inspiration from other parents who have been where you are. Know that you are not alone - our team is here to support you every step of the way.

Read Our Related Blog Posts

Select Location