Zofran and Fetal Growth Restriction

Fetal growth restriction has been reported in at least six babies who were exposed to Zofran in the womb.

Zofran and Fetal Growth Restriction

Zofran (ondansetron) is an anti-nausea drug approved for chemotherapy patients. In the last two decades, it has become a popular “off-label” treatment for pregnant women with morning sickness.

The manufacturer of Zofran, GlaxoSmithKline (GSK), has settled a civil lawsuit from the Justice Department accusing them of illegally marketing Zofran to pregnant women. The problem is that Zofran is not approved for pregnancy and its fetal safety is based on fewer than 200 births.

Unfortunately, a growing number of studies are linking Zofran with birth defects, including fetal growth restriction.

According to the Toronto Star:

“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.”

What is Intrauterine Growth Restriction?

Intrauterine Growth Restriction (IUGR), also known as “fetal growth restriction,” occurs when a fetus’s weight is in the bottom 10% percentile for its gestational age (meaning that 90% of babies of the same age weigh more).

Not all cases of IUGR are unhealthy. If the mother is small in stature, it is more likely she will have a healthy baby that is simply born smaller than average.

However, babies with IUGR can be born with serious problems if the condition is caused by a lack of oxygen or nutrients. This can happen for a number of reasons, including placental insufficiency and taking certain medications.

There are two types of IUGR:

• Symmetrical: The baby is proportionally small, meaning all parts of its body are similarly small.
• Asymmetrical: The baby has a normal-size head and brain, but the rest of its body is small.

Prognosis

Fetal growth restriction increases the risk of a premature delivery, C-section, low oxygen levels at birth, meconium aspiration, sepsis, hypoglycemia, and birth defects. Induction of delivery is often required. Once the baby is born, most have normal rates of growth. However, the lower the birth weight, the higher the risk of mental developmental problems.

Resources & Additional Information

• Identification and Management of Intrauterine Growth Restriction – American Family Physician
• What is Intrauterine Growth Restriction? – Stanford Children’s Health