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Hyperemesis Gravidarum
Key considerations: Molar pregnancy (markedly elevated hCG), Multiple gestation, Hyperthyroidism of pregnancy
Cannot miss
- Molar pregnancy (markedly elevated hCG)
- Multiple gestation
- Hyperthyroidism of pregnancy
- Appendicitis or surgical cause of vomiting
Likely diagnoses
- Hyperemesis gravidarum
- Normal nausea/vomiting of pregnancy
- Molar pregnancy
- Gastroenteritis in pregnancy
Red flags
- Weight loss >5% pre-pregnancy weight
- Ketonuria
- Electrolyte abnormalities
- Wernicke encephalopathy risk (thiamine deficiency)
- Dehydration with inability to keep fluids down
Workup
- history: Onset, severity, oral intake tolerance, weight loss, prior pregnancies, medication trials; exam: Hydration status, weight comparison, abdominal exam, thyroid exam; labs: Urine ketones and specific gravity, BMP (hypokalemia, metabolic alkalosis), LFTs, TSH, hCG level, thiamine level; imaging: Pelvic ultrasound (rule out molar pregnancy, confirm singleton); bedside: Weight, urine ketones, orthostatic vitals
Management
- immediate: IV fluid resuscitation (NS or LR); Thiamine 100mg IV BEFORE any dextrose-containing fluids; general: Antiemetic ladder: ondansetron 4-8mg IV q6h, promethazine 12.5-25mg IV/IM, metoclopramide 10mg IV q6-8h; Methylprednisolone 16mg PO/IV q8h x 3 days then taper (refractory cases); Potassium replacement; Advance diet as tolerated; Nutrition consult if prolonged
Disposition
- admit: Unable to keep oral intake, significant weight loss, electrolyte abnormalities, ketonuria not clearing with ED treatment; discharge: Tolerating oral intake after IV hydration and antiemetics with reliable follow-up; consults: OB/GYN, nutrition for severe cases
Clinical pearls
- Thiamine BEFORE dextrose in any patient with prolonged vomiting — glucose without thiamine precipitates Wernicke encephalopathy
- Transient hyperthyroidism occurs in 60% of HG due to TSH receptor stimulation by high hCG — does NOT require treatment
- HG typically resolves by 20 weeks but can persist throughout pregnancy in severe cases
Source and review
- ACOG Practice Bulletin Nausea/Vomiting in Pregnancy 2018. Last reviewed: 2024-11-01