Morning sickness, also called nausea gravidarum, nausea, vomiting of pregnancy (emesis gravidarum or NVP), or pregnancy sickness is a pregnancy discomfort that affects more than half of all pregnant women. Sometimes symptoms are present in the early hours of the morning and reduce as the day progresses. However, in spite of its common name, it can occur at any time of the day. For most women it may stop around the 12th week of pregnancy.