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Lower urinary tract obstruction (LUTO) 101

Texas Children’s Fetal Center® is a leader in the diagnosis and treatment of a rare birth defect called lower urinary tract obstruction, also known as LUTO or bladder outlet obstruction. LUTO occurs in around 2.2 of every 10,000 births, usually in males.

LUTO is a partial or complete blockage of the urethra, the tube that allows urine to exit the bladder and empty into the amniotic sac.

Babies require amniotic fluid for proper lung maturity following birth. In a baby with severe LUTO, lower levels of amniotic fluid could lead to underdeveloped lungs – a serious condition called pulmonary hypoplasia. Since the urethra is obstructed, urine overfills in the bladder and could also back up the urinary system, causing damage to the kidneys.

Symptoms and causes

The exact cause of LUTO isn’t known, but genetics could play a large role in some cases. These birth defects are more common in males than females. In fact, males are four to five times more likely to develop hydronephrosis, a less severe form of LUTO involving an obstruction in the connection between the kidney and bladder.


LUTO is typically diagnosed late in the mother’s first trimester, or early in the second trimester. Severe forms of LUTO are often diagnosed by routine ultrasounds that reveal a very large bladder and dilated kidneys. Less severe forms of LUTO, like hydronephrosis, are often diagnosed during routine prenatal ultrasounds after four months of pregnancy.


If LUTO is detected, mothers who come to Texas Children’s Fetal Center will undergo a complete two-day evaluation with a multidisciplinary team consisting of maternal-fetal medicine specialists, fetal surgeons, pediatric surgeons, neonatologists, geneticists, a pediatric nephrologist, a pediatric urologist and a pediatric cardiologist.

Treating this birth defect depends on the severity and function of the fetal kidneys, and requires highly individualized treatment tailored to both the mother and baby’s unique needs. At Texas Children’s we have some of the best outcomes in the nation due to our willingness to develop a unique, comprehensive treatment plan focused on both the medical and social costs of LUTO treatment.

Our Fetal Center provides two potential fetal intervention procedures for LUTO, including repeat bladder tap, which is uncommon, and fetal vesicoamniotic shunt placement with fetal cystoscopy. In the latter procedure, the shunt (similar to a draining tube) is inserted into the bladder of the baby while in-utero. This helps to release pressure inside the bladder and kidneys and balance fluid levels between the bladder and amniotic sac.

These babies need to be delivered in a hospital with a neonatal intensive care unit (NICU), especially since underdeveloped lungs could require breathing support.

To learn more about LUTO and Texas Children’s Fetal Center®, click here.