Ondansetron (Zofran) is a drug used by some pregnant women for nausea. There was some concern that it might cause trouble with pregnancies. An observational study was done of women in Denmark (Pasternak et al. 2013). An analysis of 1849 exposed women and 7376 unexposed women showed that 2.1% of the women exposed to ondansetron and 5.8% of the unexposed women had miscarriages during weeks 7–22 of their pregnancies.
a. Was the rate of miscarriages higher with Zofron, as feared?
b. Which of the conditions for finding the confidence interval do not hold?