April 7, 2015 — A study published over a decade ago found evidence linking the use of Zofran in pregnancy with hypospadias, but no further research has been done by GlaxoSmithKline (GSK).
The medical journal BJOG: an International Journal of Obstetrics and Gynaecology published the study, “The safety of ondansetron for nausea and vomiting of pregnancy: a prospective comparative study” in September 2004.
Researchers looked at data on 176 women who used Zofran to treat nausea and vomiting in pregnancy (NVP). There were six babies born with birth defects (3.6%), including three babies with hypospadias that needed to be treated with surgery.
According to the researchers:
“This is an increase in the rate of hypospadias in the general population (though not statistically significant), where this abnormality occurs in approximately 1 in every 300 males.”
However, none of the hypospadias were severe — two were mild and one was moderate. Furthermore, the sample size was too small to make any conclusions about whether Zofran increased the rate of hypospadia. No risk was seen in animal studies.
Even so, the researchers cautioned: “[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].”
Hypospadia is a birth defect in which the opening of the urethra is located somewhere other than the tip of the penis. It can cause a number of complications, depending on the location of the opening. If not corrected, the boy may need to urinate while sitting down. Untreated hypospadia can also cause sexual dysfunction.