Bladder Outlet Obstruction

Bladder outlet obstruction or BOO is a blockage in a baby’s bladder that restricts or prevents the flow of urine out of the body. BOO is also referred to as lower urinary tract obstruction (LUTO) and 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 BOO 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 BOO, 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 of fetal surgeons, pediatric doctors and nurses, we comprehensively monitor and treat this condition, using the safest techniques to treat your child before or after delivery.

How Is It Diagnosed?

BOO can be diagnosed as early as 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 BOO Managed During Pregnancy

After diagnosing BOO, 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. In severe cases, however, fetal surgery may be the best option as there are higher chances of kidney, bladder, and lung dysfunction because they are all linked in development through the amniotic fluid.

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

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 trusted team will help you make the best decision for your baby. 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 normal flow of urine into the amniotic fluid, allowing the lungs and kidneys to develop. There are several surgical options:

Vesicoamniotic Shunt

This is the most common fetal procedure. 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 bag of water). The shunt can increase the potential for normal function in the fetal kidneys, bladder, lungs, and amniotic cavity. This is a very safe procedure however as with all surgeries, there is the risk of complications including infections, fetal bleeding, uterine contractions, and the removal of the shunt by the baby.

Fetal Cystoscopy

This minimally invasive procedure involves the insertion of a small fiber optic scope into the fetal bladder. This scope is used to remove the fetal obstruction which improves the odds that the baby will have functional kidneys and lungs, and need less intervention after birth. The Cardinal Glennon St. Louis Fetal Care Institute is one of the few centers with the experience, and ability, to perform this particular intervention.

After surgery, your baby will require kidney ultrasounds, as well as blood and urine tests to ensure that the kidneys continue to function properly. 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.

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 314-268-4037 or toll free at 877-SSM-FETL (877-776-3385).

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