Studies and case reports have found evidence linking the anti-nausea drug Zofran with hydronephrosis (swelling in the kidneys) and other birth defects when it is used in the first trimester of pregnancy.
Normally, everyone is born with two kidneys. These bean-shaped organs are located in the middle of the back below the ribcage. They are responsible for filtering blood and removing wastes, toxins, and excess water by excreting them in urine.
Zofran and Hydronephrosis
In June 2014, an investigation by the Toronto Star reported on at least 20 cases of birth defects associated with Zofran, including kidney defects:
“At least 20 Canadian women treated with ondansetron for vomiting in pregnancy experienced serious suspected side-effects, including two infant deaths and multiple cases of newborns with heart defects and kidney malformations.”
The use of Zofran during the first trimester was also associated with a 20% increased risk of birth defects in a study published by BioMed Research International in December 2013.
The researchers also observed a 6-fold increase in the rate of kidney defects associated with Zofran described as “obstructive defects of renal pelvis and ureter,” suggesting a risk of hydronephrosis.
However, the study was too small to draw any conclusions about individual birth defects. Conclusions were based on about 250 pregnant women who used Zofran in Western Australia from 2002-2005.
What is Hydronephrosis?
Hydronephrosis (which means “water in the kidneys”) is a condition that occurs when urine backs up inside the kidneys, resulting in swelling and distention.
Symptoms of Hydronephrosis
- Abdominal pain
- Nausea and vomiting
- Painful urination
- Frequent urination
- Urinary tract infections
When hydronephrosis causes an infection, symptoms may include back pain, high fever, and urination that is weak, cloudy, and painful.
Hydronephrosis is a relatively common congenital condition, but does not always cause problems. Many cases resolve without treatment soon after birth. However, when hydronephrosis is caused by an obstruction, serious complications can occur.
Over time, untreated hydronephrosis can damage delicate tissues inside the kidneys and cause recurrent urinary tract infections (UTI), necrosis, and kidney failure. The only treatment for kidney failure is an organ transplant from a healthy donor.
In newborns, hydronephrosis is often diagnosed with an ultrasound or CT scan. These medical tests are used to create a 3D image of the kidneys and swelling.
Surgical treatment may be necessary when hydronephrosis is caused by a blockage or narrowing in the ureters, which are tubes that drain urine from the kidneys to the bladder, or obstructions in the bladder itself.
Some cases can be treated by insertion of a ureteral stent (allows urine to drain to the bladder) or nephrostomy tube (allows urine to drain to the back).