Nausea (feeling sick) and vomiting (being sick) is one of the most common side effects of pregnancy, specifically in early pregnancy. It has previously been called morning sickness, but this isn't an accurate name because it often lasts all day. About 9 out of 10 pregnant women experience morning sickness in some way, either feeling sick (nausea) or being sick (vomiting), or both. For most women this unpleasant problem starts at around 6-7 weeks of pregnancy, and is better by week 14.
This is a companion discussion topic for the original article at https://patient.info/pregnancy/common-problems-in-pregnancy-leaflet