Nausea and vomiting are common during the early stages of pregnancy, thought to be due to the hormonal changes that occur during early embryonic development when there are increasing levels of oestrogen and human chorionic gonadotrophin. Antiemetic agents (i.e. those that stop you being sick) were previously widely used but are now avoided for fear of producing abnormalities in the foetus. The symptoms may be reduced by eating little and often, avoiding strongly spiced or highly aromatic dishes, and having a snack and a drink before rising from bed in the morning. Many women find that the problem disappears once embryonic development is over at around about the 10th week, though some continue to suffer on and off throughout the whole pregnancy. It is important to maintain fluid input.