Nauseated

 I'm pregnant with my third. I had bad morning sickness with my first but I never took my medicine that was prescribed to me because I was skeptical about taking anything. I wasn't working and could lay in bed without distraction so it worked out. My second no morning sickness. With this one I have morning sickness with constant nausea which is a problem because  I work as well as have to keep up with my older two. I took one zofran last night and my symptoms were gone almost instantly but I read that it could be linked to birth defects. Does/did anyone take zofran/ondansetron while pregnant?