Makindo Medical Notes

Hyperemesis gravidarum (HG) = severe, persistent nausea and vomiting in pregnancy → leads to weight loss, dehydration, and electrolyte imbalance. ⚠️ It is more severe than typical “morning sickness” and often requires hospital care. Incidence: ~1 in 100 pregnancies in the UK.

🧬 Pathophysiology

• Linked to high β-hCG and oestrogen levels (peaks in first trimester).
• More common in multiple pregnancy 👶👶, molar pregnancy, and women with personal/family history of HG.
• Possible role of genetic, thyroid, and gut motility factors.

📋 Clinical Features

• Persistent nausea and vomiting 🤢 (cannot tolerate oral intake).
• Weight loss >5% of pre-pregnancy weight ⚖️.
• Signs of dehydration: dry mucous membranes, tachycardia, hypotension.
• Electrolyte imbalance → hypokalaemia, hyponatraemia.
• Ketonuria (starvation ketosis) on urine dipstick.
• May present with dizziness, fatigue, and reduced urine output.

🔍 Investigations

• 🧪 Urine dipstick: ketones, specific gravity.
• 🩸 Bloods: U&E (K⁺, Na⁺), LFTs, FBC (exclude infection/anaemia), TFTs (hCG can cause transient hyperthyroidism).
• 💉 Venous blood gas: check for metabolic alkalosis or acidosis.
• 🖥️ Ultrasound: exclude multiple pregnancy and trophoblastic disease.

⚕️ Management

• 🏥 Hospital admission if unable to tolerate oral fluids, ketonuria, or electrolyte imbalance.
• 💧 IV fluids: Normal saline + KCl (avoid dextrose without thiamine → risk of Wernicke’s encephalopathy).
• 💊 Antiemetics (per RCOG/NICE):
  • First-line: antihistamines (cyclizine, promethazine) or prochlorperazine.
  • Second-line: metoclopramide, ondansetron.
  • Severe/refractory: corticosteroids (e.g. hydrocortisone → prednisolone taper).
• 💉 Thiamine supplementation (100 mg IV or oral) for all women with prolonged vomiting to prevent Wernicke’s encephalopathy.
• 🥤 Nutritional support: enteral feeding if prolonged HG; rarely TPN needed.

🚩 Complications

• Maternal: dehydration, electrolyte imbalance, Wernicke’s encephalopathy, Mallory–Weiss tears, thromboembolism.
• Fetal: intrauterine growth restriction (IUGR), low birth weight, preterm birth (if severe and prolonged).

📌 Prognosis

• Usually improves by 16–20 weeks, but may persist throughout pregnancy in some women.
• Recurs in subsequent pregnancies in up to 15–20%.
• Supportive care and reassurance are crucial.

📖 Clinical Pearls

• 💡 Always give thiamine before IV dextrose.
• ❌ Avoid ondansetron in first trimester unless refractory (possible small risk of cleft palate, though evidence is mixed).
• ⚠️ Molar pregnancy → suspect if HG is severe, very early, or with large-for-dates uterus.
• 👩‍⚕️ Multidisciplinary support (dietitians, obstetricians, mental health support) is key.

📚 References

• RCOG Green-top Guideline No. 69: Nausea and Vomiting in Pregnancy
• NICE CKS: Nausea and Vomiting in Pregnancy
• BMJ Best Practice: Hyperemesis gravidarum