Fetal Shunt Reduces Urinary Obstruction

Tube can help treat birth defect in male fetuses

(RxWiki News) Good news for pregnant moms carrying a baby with a rare birth defect affecting the urethra: treatment using a small tube called a shunt can reduce serious health risks for your baby.

Researchers from the University of Birmingham, School of Clinical and Experimental Medicine, in England, studied 145 women pregnant with a single male baby who had fetal bladder outflow obstruction, also known as lower urinary tract obstruction (LUTO).

They found that treatment with a fetal shunt led to improved survival in the babies.

"Pregnant moms should ask their doctor about fetal urinary obstruction."

LUTO is a rare birth defect that occurs in 1 in 5,000-7,000 births, and happens when there’s a partial or complete blockage of the flow of urine in an unborn baby, according to the National Institutes of Health (NIH).

This causes the urine to back up and the ureters and kidneys to swell. Treatment depends on the severity of the blockage, but it can include use of a prenatal shunt that’s inserted in the baby’s bladder to release urine into the amniotic sac.

In the English study, 31 women were randomly assigned to one of two treatments: 16 received a fetal vesico-amniotic shunt (insertion into bladder of the fetus) and 15 did not receive the treatment as a control group.

The other participants were part of a registry study in which data is collected but treatment is not predefined (46 women), or opted to terminate the pregnancy because the baby’s health was in danger (68 women). 

Many women whose babies have LUTO choose to terminate the pregnancy, say the study authors.

Here's what the team found: Of the 31 women, 39% of the babies were alive at 28 days old; 16% of the women opted to terminate the pregnancy; 6% miscarried; and 36% of the babies died before 28 days. 

Dr. Rachel Morris, a research fellow at the University of Birmingham’s Department of Obstetrics and Gynecology at Birmingham Women’s hospital, and colleagues conclude that babies have a 4.0 improved odds ratio of survival with shunting.

LUTO is detected during an ultrasound examination, according to NIH. The doctor might notice swelling in the baby’s kidneys (hydronephrosis), which reduces the developing kidneys’ ability to filter waste. It will also raise the risk of the baby developing a urinary tract infection.

Doctors recommend use of a prenatal shunt if the urine blockage threatens the life of the unborn baby. The surgery carries risks and is only performed when the baby’s lungs aren’t developing or when the kidneys are severely damaged, says NIH.

Other treatment options for LUTO include antibiotics, surgery and intermittent catheterization, in which a catheter, or tube, is inserted to empty the bladder.

Funding was through the Health Technology Assessment program of the United Kingdom.

Review Date: 
February 9, 2012