What factors likely cause nausea and vomiting in a woman at 9 weeks gestation?

Nausea and vomiting during early pregnancy, often referred to as "morning sickness," can indeed be influenced by various hormonal changes and metabolic factors. While altered carbohydrate metabolism can contribute to these symptoms, recent research heavily points to hormonal fluctuations as primary contributors to the feelings of nausea and vomiting.

At 9 weeks gestation, the levels of hormones such as estrogen and human chorionic gonadotropin (hCG) are significantly elevated. hCG, in particular, is produced shortly after conception and peaks during the first trimester. Many studies indicate a correlation between high levels of hCG and the onset of nausea and vomiting in pregnant women. The rise in this hormone seems to stimulate the activity of the gastrointestinal tract, which may lead to these unpleasant symptoms.

Increased levels of estrogen do play a role in the overall changes in the body during pregnancy, but the specific mechanisms linking this hormone to nausea are not as direct or well-established as those associated with hCG. Consequently, identifying altered carbohydrate metabolism alone as the primary cause of nausea overlooks the significant impact that rising hormone levels have on a pregnant woman's physiology.

While each of the factors mentioned may contribute to the overall experience of pregnancy, the elevation in hCG has the most considerable evidence pointing towards its direct