Zofran and Fetal Growth Restriction

Recent case reports have identified at least six cases of Fetal Growth Restriction in babies who were exposed to Zofran in the womb.

Case Reports Link Zofran and Fetal Growth Restriction

Zofran (ondansetron) is a prescription medication for the treatment of nausea caused by chemotherapy. It is also commonly used “off-label” by pregnant women for the treatment of morning sickness.

Unfortunately, a growing number of studies and case reports suggest that Zofran may pose birth defect risks to a fetus when it is used during pregnancy.

In a review of birth defects linked to Zofran, the Toronto Star has found at least six case 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.”

The problem is that GlaxoSmithKline (GSK), the manufacturer of Zofran, has only tested it in pregnant rats and rabbits back in 1985. There are no adequate, well-controlled studies in pregnant women. No one knows if Zofran is safe to use during pregnancy.

What is Fetal Growth Restriction?

Fetal growth restriction, also known as “intrauterine growth restriction” (IUGR), is a condition that occurs when a fetus weighs less than 90% of other fetuses of the same gestational age.

The condition does not necessarily cause medical problems. For example, a mother who is very small may have a healthy baby that is simply smaller than average.

However, the smaller a baby is when it is born, the higher the risk of serious medical problems — especially if the condition is caused by low oxygen, nutrients, placenta problems, or medications.

Types of fetal growth restriction:

• Symmetrical: The baby is proportionately smaller than average.
• Asymmetrical: The baby is disproportionately small, often with a normal-sized head and brain but a smaller body.

Outlook

The outlook for growth-restricted babies depends on the severity of the condition and its cause. All babies with this condition have a higher risk of premature birth and C-section delivery. After birth, most grow and develop normally into childhood. However, babies that are very small are more likely to have developmental delays.

Resources & Additional Information

• Intrauterine Growth Restriction – Academy of American Family Physician (AAFP)
• Fetal Growth Restriction (FGR) – University of Rochester Medical Center