April 7, 2015 — Nearly a decade ago, a study found case reports linking the use of Zofran during pregnancy and a birth defect known as hypospadia, but this risk was never investigated by GlaxoSmithKline (GSK).
Zofran has been on the market since the early 1990s, but its safety in pregnant women has never been evaluated by GSK.
One of the first studies to investigate the risk of birth defects was published in September 2004, but it was based on only 176 women who used Zofran in the first trimester. The study was not large enough to make any conclusions about specific birth defects.
After excluding pregnancies that did not come to term, six women (3.6%) had babies with “major” birth defects — including three babies who were born with hypospadia and needed surgery.
The number of cases of hypospadia was unusually high, considering that the defect normally only occurs in 1 out of 300 births. The researchers warned:
“[Zofran] was never intended or labeled as such to be a treatment for NVP. Consequently, there is a paucity of data in the literature on the safety of [Zofran].”
The study was published by the medical journal BJOG: an International Journal of Obstetrics and Gynaecology, and titled “The safety of ondansetron for nausea and vomiting of pregnancy: a prospective comparative study.”
Hypospadia is a serious birth defect that involves a urethral opening somewhere other than at the tip of the penis. It almost always requires surgery. Without treatment, boys with hypospadia may have to urinate sitting down and they may have sexual dysfunction as adults.