Morning sickness

Morning sickness, also called nausea and vomiting of pregnancy, is a symptom of pregnancy. Despite the name, nausea or vomiting can happen at any time of day. Symptoms typically occur between the fourth and sixteenth weeks of pregnancy, and about 10 percent of women still have them after the twentieth week. A severe form, hyperemesis gravidarum, causes weight loss and occurs in about 1.6 percent of pregnancies. The cause is unknown but may relate to changing levels of human chorionic gonadotropin, and some have proposed an evolutionary benefit. Roughly 70 to 80 percent of pregnant women are affected to some extent and about 60 percent vomit. Diagnosis comes only after other causes are ruled out. Mild to moderate cases generally do not affect the fetus. A bland diet may be all that is needed for mild cases; the combination of doxylamine and pyridoxine is recommended first when drugs are used, and ginger has limited supporting evidence.