Hi, Of course, use of Duromine is not advised during pregnancy because Phentermine, the active ingredient of Duromine acts on so many biological processes as well as metabolic activities. Moreover, it also acts on brain signals for appetite. Therefore, it may disturb the beneficial biological and metabolic activities of pregnancy, affecting the normal development of fetus. As phentermine also causes the weight loss, which is not desired during pregnancy. It causes also dehydration and may result in unwanted effects of deranged water and mineral metabolism, on the fetus. Dehydration may also result in constipation, which may be an annoying symptom during pregnancy. However, with all the studies available, there seems no teratogenic effect of this drug on the fetus. Hence, I do not think, that this is an indication of termination of pregnancy. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Satnarain Bansal, General & Family Physician