Define hyperemesis gravidarum and distinguish it from nausea and vomiting of pregnancy. Describe the epidemiology, risk factors, and pathophysiology of hyperemesis gravidarum. Identify the clinical features and warning signs of severe hyperemesis gravidarum, including dehydration, electrolyte disturbances, and nutritional deficiencies. Outline the diagnostic approach, including clinical assessment, laboratory investigations, and exclusion of alternative causes of persistent vomiting in pregnancy. Discuss the principles of management, including fluid resuscitation, electrolyte correction, antiemetic therapy, and nutritional support. Explain the importance of administering thiamine before dextrose-containing fluids or nutritional support in women with prolonged vomiting or poor nutritional intake. Recognize maternal and fetal complications, including acute kidney injury, Wernicke encephalopathy, malnutrition, and adverse pregnancy outcomes. Identify indications for hospital admission, specialist referral, and escalation of treatment in severe or refractory cases. Describe strategies for follow-up, prevention of recurrence, and supportive care to improve maternal wellbeing and pregnancy outcomes.