Zofran Kidney Defects

Zofran may increase the risk of major kidney birth defects by 480%

Australian study: Zofran during pregnancy a major factor in risk of kidney birth defects.

Zofran during pregnancy has been found to increase the risk of major kidney defects up to 620% above the normal rate.

Researchers from the University of Australia undertook to study the safety of Zofran (Ondansetron) use during pregnancy after becoming concerned of the increasing trend to prescribe Zofran absent scientific data establishing its safety.   Of the 98,968 pregnancies in Western Australia from 2002-2005, 251 pregnancies involved women using Zofran during the pregnancy.

In addition to finding a 20% increase in total major birth defects from Zofran pregnancies, the study also found a 620% risk of obstructive defects of renal pelvic and ureter.  This means that children born to women using Zofran during pregnancy were found to have six times the rate of these kinds of kidney defects as compared to those born to women who did not take Zofran during pregnancy.

Obstruction of the kidney in a newborn is a serious condition as it can result in the need for surgery, the loss of function in one or both kidneys, the loss of the organ or organs, and can even result in the death of a child.  GlaxoSmithKline, the manufacturer of Zofran, profited from years of promoting off-label usage to treating nausea during pregnancy, and put thousands of pregnant women and their infants at risk for such kidney birth defects.   Despite these astonishingly high risks for birth defects, GlaxoSmithKline has never provided warnings to these women or their prescribing doctors.   These risks thus remain hidden from pregnant women today.

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[UPDATE]: Levin Simes is not currently investigating Zofran for kidney defects. Levin Simes continues to investigate Zofran for heart defect and cleft palate defects. We hope the information on this page is informative of the potential risks of Zofran during pregnancy.

Learn More about Kidney Birth Defects Caused by Zofran Pregnancy

Urinary Blockage

There are many forms of urinary blockage in newborns.  The urinary tract is the body’s system for draining and removing waste and excess fluids.  The system consists of two kidneys, which then run fluids through the two ureters into the bladder, which can then be emptied (voided) via the urethra.  Your kidneys will filter up to 150 quarts of blood per day in order to produce 1-2 quarters of urine, a critical and lifesaving process to remove waste and extra fluid.

There are many ways urinary blockage can occur:

  • Ureterocele: A bulge at the end of a ureter that did not develop normally, it can obstruct part of the ureter or bladder.
  • Bladder Outlet Obstruction (BOO): A bladder outlet obstruction is a blockage in the urethra or at the opening of the bladder. The most frequent version is a defect in newborn boys where a fold of tissue in the urethra prevents urine from flowing out of the bladder. This can cause swelling in the urinary tract, urethra, bladder, ureters, and kidneys.
  • Uretropelvic Junction (UPJ) Obstruction: When urine is blocked where the ureter meets the kidney, the kidney will begin to swell. This is more frequently seen occurring in a single kidney than in both kidneys.
  • Vesicoureteral Reflux: If a child is born with a ureter that is not long enough, the valve between the ureter and the bladder will fail to close fully, resulting in urine reflux. The term reflux here is used in the same way it is for acid reflux. In the same way heartburn can be caused by acid refluxing back up the system, urine reflux means urine is working backwards through the system and flowing back into the kidneys. Severe cases of urine reflux can prevent the full development of the kidney and increase the risk of infection or continued damage after birth. This type of defect is more typically seen in one kidney but not both.

Hydroureter & Hydronephrosis

When urine blockage occurs, hydroureter and hydronephrosis can occur.

Hydroureter is the swelling of the urethra caused by the blockage and the backward flow of urine:


Hydronephrosis is the swelling of the kidney, also caused by the blockage of urine.  Hydronephrosis can be discovered during prenatal ultrasounds. When hydronephrosis occurs, it can be mild or it can be severe enough to impact the future filter capabilities of the newborn’s kidneys.  Since the kidney output in the womb is part of the amniotic fluid, a severe blockage during development can result in such a reduction in the amount of fluid available that it impacts the development of other organs, namely the newborn’s lungs which require the fluid in the womb.  Post birth, risks for urinary tract infections (UTI) increase and recurrent UTIs can cause additional kidney damage, including new permanent kidney damage.

What is the Treatment for Urinary Blockage?

When urinary blockage is diagnosed, whether before birth from an ultrasound or amniocentesis, or after birth via ultrasound or a cystourethrogram, there are several treatment options. The treatment method is usually determined by the severity of the blockage.

Severe cases of blockage discovered prior to birth may require the placement of a shunt or tube into the womb.  Due to the risks of surgery on an unborn baby, surgery prior to birth is typically reserved for the most serious cases, such as when the urine blockage is complete and preventing any amniotic fluid from developing, which in turn may prevent the full development of the child’s lungs.

If the concern is post-birth UTIs, antibiotics can be used to treat or prevent instances of urinary tract infections, which should be avoided to prevent infections as recurrent infections can create damage to the ureter or kidneys.

If after birth the defect does not correct itself, surgery on the infant may be necessary to remove the blockage and allow for proper movement of urine.  Once the obstruction is removed, a small stent or tube is sometimes placed during the recovery period to allow the ureter to remain open.

Link between heart defects and kidney defects

Children who are born with birth defects of the heart are also known to have higher risks of ureter or kidney defects including blockage.  Zofran during pregnancy has been studied and found to cause anywhere from a 60% increase (in overall heart defects) to a 380% increase (septal defects including arterioventrciularseptal defects) in heart defects.  It is unknown if the increase in birth defects of the heart from taking Zofran during pregnancy is linked to the increased kidney birth defects from taking Zofran during pregnancy, but they are known to be associated and the cause may be related.

Zofran Kidney Defect Lawsuits

[UPDATE]: Levin Simes is not currently investigating Zofran during pregnancy for kidney defects. This page is intended to provide information about the potential risks of Zofran.