"Morning sickness" or a sense of nausea with or without vomiting
, is a very common symptom in early pregnancy. When this progresses to a point where the woman is unable to undertake normal activities or unable to support her nutritional or fluid needs because of vomiting, it is termed "hyperemesis gravidarum." Hyperemesis gravidarum can be very profound, to the point of requiring hospitalization for IV fluids, total parenteral nutrition (food given through the veins) and anti-nausea medications.
The specific cause of morning sickness is not clearly known, and there are likely many factors at work that produce morning sickness. The presence of one hormone, however, has been clearly associated with morning sickness. This hormone is called beta-hCG, and is produced in the placenta - it is the same hormone used to diagnose pregnancy in a urine test or a doctor's office blood test. The levels of beta-hCG usually decline by the end of the first trimester (first 14 weeks of being pregnant, which is usually around 16 weeks since your last period), and most women report resolution of their morning sickness by that time.
If your symptoms of morning sickness persist beyond the first trimester, if they are so profound that you are unable to keep food or drink down, or if you have any other concerning symptoms, you should seek an in-person consultation with your OB/GYN. Medications can be given to help treat the nausea, and your OB/GYN will be able to counsel you on warning signs or symptoms, as well as some common ways of coping with morning sickness.