Investigation Links Zofran and 475 Reports of Birth Defects

July 17, 2015 — Zofran has been linked to 475 reports of birth defects and adverse fetal events since it was approved in 1991, according to reports submitted to the FDA and reviewed by Monheit Law.

Out of 475 reports, 170 involved congenital heart defects or cardiovascular abnormalities. The most common heart defects were atrial or ventricular septal defects (“hole in the heart”).

Zofran has been linked to heart defects before. One study (PDF) published by researchers from Denmark found the following increased risks:

• 2.1-fold increased risk of atrial septal defect
• 2.3-fold increased risk of ventricular septal defect
• 4.8-fold increased risk of atrioventricular septal defect

Zofran has also been linked to craniofacial birth defects. Investigators found over 50 reports of these defects, including cleft lip, cleft palate, microcephaly (abnormally small head), and Robin’s Syndrome (cleft palate and other defects).

Recent studies have already linked Zofran with an increased risk of cleft palate. In 2012, researchers looked at data from the National Birth Defects Prevention Study and concluded that babies were 2.4-times more likely to be born with cleft palate if they were exposed to Zofran in the womb.

Monheit also found 63 references to fetal growth restriction, in which fetal weight is below the 10th percentile for gestational age. A separate investigation by the Toronto Star found at least six reports of fetal growth restriction:

“Four of the Canadian babies featured in the FDA side-effect reports reviewed by the Star were born weighing as little as four-and-a-half pounds. In six cases, a suspected side-effect of ondansetron was listed as “fetal growth restriction.”

Monheit found evidence of other adverse fetal outcomes, including 86 references to congenital respiratory defects, neonatal respiratory distress syndrome, and pulmonary hypoplasia. Other adverse outcomes included fetal death, stillbirth, miscarriage, premature delivery.