Nausea after eating breakfast is caused by indigestion, stomach cramps. 1, some women are symptoms of early pregnancy, the human body exists in indigestion, the food into the stomach can not be emptied in time and stay in the stomach. When the food reacts with the digestive juices in the stomach, fermentation occurs, which not only increases the volume, but also produces too much gas, which irritates the stomach lining and causes nausea.2. Some people eat stimulating foods in their diet, which irritate the gastric mucosa and lining of the stomach and induce strong contractions and spasms in the stomach, and nausea occurs when the contents of the stomach are squeezed.3. Hormonal changes occur in the body of a woman in the early stages of pregnancy, which can affect the gastrointestinal system and the body’s ability to function. Changes in hormone levels in the body during early pregnancy will affect the gastrointestinal system, and many women will experience nausea and vomiting during early pregnancy, especially in the morning.