Hyperemesis Gravidarum
Hyperemesis gravidarum (HG) = severe, persistent nausea and vomiting in pregnancy โ leads to weight loss, dehydration, and electrolyte imbalance.
โ ๏ธ It is more severe than typical โmorning sicknessโ and often requires hospital care.
Incidence: ~1 in 100 pregnancies in the UK.
๐งฌ Pathophysiology
- Linked to high ฮฒ-hCG and oestrogen levels (peaks in first trimester).
- More common in multiple pregnancy ๐ถ๐ถ, molar pregnancy, and women with personal/family history of HG.
- Possible role of genetic, thyroid, and gut motility factors.
๐ Clinical Features
- Persistent nausea and vomiting ๐คข (cannot tolerate oral intake).
- Weight loss >5% of pre-pregnancy weight โ๏ธ.
- Signs of dehydration: dry mucous membranes, tachycardia, hypotension.
- Electrolyte imbalance โ hypokalaemia, hyponatraemia.
- Ketonuria (starvation ketosis) on urine dipstick.
- May present with dizziness, fatigue, and reduced urine output.
๐ Investigations
- ๐งช Urine dipstick: ketones, specific gravity.
- ๐ฉธ Bloods: U&E (Kโบ, Naโบ), LFTs, FBC (exclude infection/anaemia), TFTs (hCG can cause transient hyperthyroidism).
- ๐ Venous blood gas: check for metabolic alkalosis or acidosis.
- ๐ฅ๏ธ Ultrasound: exclude multiple pregnancy and trophoblastic disease.
โ๏ธ Management
- ๐ฅ Hospital admission if unable to tolerate oral fluids, ketonuria, or electrolyte imbalance.
- ๐ง IV fluids: Normal saline + KCl (avoid dextrose without thiamine โ risk of Wernickeโs encephalopathy).
- ๐ Antiemetics (per RCOG/NICE):
- First-line: antihistamines (cyclizine, promethazine) or prochlorperazine.
- Second-line: metoclopramide, ondansetron.
- Severe/refractory: corticosteroids (e.g. hydrocortisone โ prednisolone taper).
- ๐ Thiamine supplementation (100 mg IV or oral) for all women with prolonged vomiting to prevent Wernickeโs encephalopathy.
- ๐ฅค Nutritional support: enteral feeding if prolonged HG; rarely TPN needed.
๐ฉ Complications
- Maternal: dehydration, electrolyte imbalance, Wernickeโs encephalopathy, MalloryโWeiss tears, thromboembolism.
- Fetal: intrauterine growth restriction (IUGR), low birth weight, preterm birth (if severe and prolonged).
๐ Prognosis
- Usually improves by 16โ20 weeks, but may persist throughout pregnancy in some women.
- Recurs in subsequent pregnancies in up to 15โ20%.
- Supportive care and reassurance are crucial.
๐ Clinical Pearls
- ๐ก Always give thiamine before IV dextrose.
- โ Avoid ondansetron in first trimester unless refractory (possible small risk of cleft palate, though evidence is mixed).
- โ ๏ธ Molar pregnancy โ suspect if HG is severe, very early, or with large-for-dates uterus.
- ๐ฉโโ๏ธ Multidisciplinary support (dietitians, obstetricians, mental health support) is key.
๐ References
