Vomiting in first trimester common; only HG if excessive, protracted, altering quality of life

Pathophysiology

• The placenta produces hCG during pregnancy
• This hormone is thought to be responsible for nausea and vomiting
• Nausea and vomiting are more severe in molar pregnancies and multiple pregnancies due to the higher hCG levels
• It also tends to be worse in the first pregnancy and overweight or obese women

Clinical features

• Dehydration, ketosis, electrolyte and nutritional disbalance
• Weight loss, altered liver function
• Signs of malnutrition
• Emotional instability, anxiety, severe cases can cause mental health issues e.g. depression

Investigations

• The RCOG guideline (2016) criteria for diagnosing hyperemesis gravidarum are ‘protracted’ NVP plus:
  • More than 5% weight loss compared with before pregnancy
  • Dehydration
  • Electrolyte imbalance
• Severe HG may be associated with fetal growth restriction, hence growth scans are advised

Management

• Rehydration IV, electrolyte replacement
• Parenteral antiemetic
  • First line: cyclizine, prochlorperazine
  • Second line: metoclopramide
• Nutritional supplement
• Vitamin supplement: thiamine/pabrinex
• NG feeding, Total Parenteral Nutrition (TPN)