My wife is pregnant via IVF. She has twins and 6 week pregnancy. She is suffering from severe nausea and vomiting, taking doxinate tablet BD but no improvement shown, ondansetron 4 mg bd also failed but granisetron 1 mg works well. I want to ask that taking granisetron in pregnancy is safe or not and how long can my wife take it and what is the exact dose? Please tell me. I am so much worried.