Why does hyperemesis gravidarum cause morning sickness?

Hyperemesis gravidarum is a severe form of pregnancy sickness. Hormonal changes can affect the stomach, brain pathways, and the areas that coordinate vomiting. Some people are especially sensitive to these signals, so nausea can continue beyond the morning and vomiting can become frequent.

Repeated vomiting may cause dehydration, loss of salts, poor food intake, and weight loss. These effects can then worsen weakness and nausea, creating a cycle that needs medical support. The severity is judged by symptoms and examination, not by the time of day alone.

Contact your maternity or medical team if nausea prevents normal drinking or eating. They may suggest small, frequent sips, bland foods when tolerated, rest, and pregnancy-safe anti-sickness treatment. Do not stop prescribed medicines without advice. Treatment may include fluids and replacement of body salts when vomiting has caused dehydration.

Seek urgent medical help if you cannot keep fluids down, pass very little urine, feel faint or confused, have a racing heartbeat, vomit blood, or develop severe abdominal pain or fever. These signs can indicate dehydration or another condition requiring prompt assessment.

Ask which anti-sickness medicines are suitable, how to recognise dehydration, whether your urine and blood salts need checking, and when intravenous fluids or hospital assessment would be considered.