what is nausea in pregnancy

Nausea and vomiting of pregnancy, commonly known as morning sickness, is a common symptom of pregnancy that typically occurs between the 4th and 16th week of pregnancy. Despite the name, it can occur at any time during the day. It is estimated to affect about 75% of pregnancies, and most women experience relief by the 16th to 20th week of pregnancy. A severe form of this condition, known as hyperemesis gravidarum, can result in weight loss and may require specialist treatment, sometimes in the hospital