Hyperemesis Gravidarum — Inpatient Order Set (Example)

1. Location & Level of Care

• Admit to: ☐ Antepartum / OB ward   ☐ Day-stay infusion unit   ☐ Step-down / high-acuity OB unit
• Nursing level of care: ☐ Standard   ☐ Intermediate / 1:3   ☐ Higher acuity (frequent vitals / infusion titration).
• OB/MFM service: ☐ Primary team   ☐ Consulted.
• Additional consults as indicated: ☐ Nutrition   ☐ Psychiatry/behavioral health   ☐ Gastroenterology   ☐ Internal medicine.

2. Diagnosis, Severity & Initial Orders

• Confirm working diagnosis: Hyperemesis gravidarum (clinical diagnosis of exclusion; document weight loss, duration of vomiting, ketonuria, and electrolyte abnormalities).
• Rule out other causes of nausea/vomiting: e.g., multiple gestation, molar pregnancy, appendicitis, pancreatitis, bowel obstruction, pyelonephritis, intracranial pathology, thyroid disease, diabetic ketoacidosis, COVID-19, medication effects.
• Record gestational age, plurality, and prior history of hyperemesis.
• Vital signs at least every 4 hours (more frequently if hemodynamically unstable): HR, BP, RR, SpO₂, temperature.
• Strict intake/output; document urine output hourly initially if significantly dehydrated.
• Consider use of standardized symptom/severity tool (e.g., PUQE or local HG scale) on admission and daily to track response.
• Establish: ☐ Peripheral IV (preferably 2 lines)   ☐ PICC / midline if prolonged therapy anticipated.

3. Labs & Diagnostic Studies

Serial Monitoring

• BMP (Na, K, Cl, CO₂, BUN, Cr) and Mg/Phos: q 24 hours (or more frequently during active repletion or high-dose IV therapy).
• Daily weight and orthostatic vitals.

4. IV Fluids & Electrolyte Replacement

Avoid glucose-containing fluids until thiamine has been given in patients with prolonged vomiting or poor intake, to reduce risk of Wernicke’s encephalopathy and refeeding syndrome.

• Initial resuscitation (no overt fluid overload):
  • Isotonic crystalloid (e.g., normal saline or Lactated Ringer’s) 1–2 L over first 2–3 hours, then adjust to clinical response and comorbidities.
• Ongoing maintenance:
  • Typical rate 75–125 mL/hour isotonic fluid; titrate to vitals, urine output (goal ≥ 0.5 mL/kg/hour), and cardiac status.
• Potassium replacement per institutional protocol:
  • Add KCl to IV fluids or administer as separate infusion based on serum K and renal function.
• Magnesium and phosphate replacement per protocol; monitor for hypocalcemia with phosphate repletion.
• Once some rehydration achieved, consider IV solutions containing dextrose (e.g., D5 0.45% NaCl) to provide calories after thiamine supplementation.

5. Vitamins, Thiamine & Nutrition

Thiamine deficiency and malnutrition are key drivers of neurologic and maternal–fetal complications in refractory hyperemesis; prophylactic supplementation is strongly recommended in admitted patients with prolonged vomiting.

• Thiamine (Vitamin B₁) for all inpatients with several days of reduced intake or weight loss:
  • Thiamine 100 mg IV daily (or with each day of IV fluids) before dextrose-containing solutions, then transition to oral thiamine (e.g., 50–100 mg PO 1–3 times daily) when tolerating PO.
  • Higher doses and longer duration may be indicated in severe cases per neurology or institutional protocol.
• Multivitamin supplementation:
  • IV multivitamin (in IV fluids) or oral prenatal vitamin when tolerated.
  • Consider additional folate, vitamin B₆, and other micronutrients if evidence of deficiency.
• Nutrition:
  • Diet: small, frequent meals; high-protein, complex carbohydrates; avoid triggers identified by patient.
  • Resume oral intake as soon as tolerated; consider “trial of sips” followed by light diet.
  • Nutrition consult for patients with > 5–10% weight loss, prolonged symptoms, or inability to meet caloric needs.
  • Consider enteral nutrition (e.g., nasogastric/nasojejunal feeding) if persistent inability to maintain weight and hydration despite maximal medical therapy.
  • Parenteral nutrition reserved for refractory cases after multidisciplinary discussion (MFM, nutrition, pharmacy, and, if applicable, ethics/psychology).

6. Antiemetic Therapy (Stepwise, Multimodal)

Use a stepwise approach, often combining agents from different classes. Adjust for prior response, comorbidities, QT interval, and patient preferences.

6A. First-Line (Often Outpatient/Day-Unit)

• Pyridoxine ± doxylamine:
  • Pyridoxine (vitamin B₆) 10–25 mg PO every 6–8 hours.
  • Doxylamine 12.5 mg PO every 6–8 hours (or combination product per local formulary).
• Counsel to take on a scheduled (not PRN-only) basis initially.

6B. Second-Line / Inpatient Antiemetics

• Antihistamines (H₁):
  • Dimenhydrinate, diphenhydramine, or meclizine PO/IV per institutional dosing (watch for sedation).
• Phenothiazines:
  • Promethazine or prochlorperazine PO/PR/IV per protocol; monitor for extrapyramidal side effects and sedation.
• Dopamine antagonist:
  • Metoclopramide 5–10 mg PO/IV every 6–8 hours (short-term use preferred; monitor for EPS and tardive dyskinesia with prolonged therapy).
• 5-HT₃ antagonist:
  • Ondansetron (e.g., 4–8 mg PO/ODT/IV every 8 hours), considering gestational age, risk–benefit, and QT interval.
• Acid suppression (adjunct):
  • H₂ blocker (e.g., famotidine) or PPI for reflux/gastritis, which can exacerbate nausea.

6C. Refractory / Third-Line (Specialist Guidance)

• Corticosteroids for refractory hyperemesis (after failure of other classes and typically after 10 weeks’ gestation due to theoretical oral-cleft risk):
  • Example: methylprednisolone 16 mg PO/IV every 8 hours for 3 days, then gradual taper to lowest effective dose per specialist and guideline recommendations.
• Consider other adjunctive agents (e.g., mirtazapine in selected cases with severe weight loss and comorbid depression) in consultation with psychiatry/MFM.
• Avoid routine use of benzodiazepines and opioids; reserve for specific indications and shortest duration.

7. Pregnancy-Specific & Fetal Monitoring

• Confirm gestational age, fetal number, and viability on admission (if not already documented).
• Fetal surveillance:
  • Pre-viable: intermittent Doppler FHR documentation.
  • Viable: non-stress testing or continuous electronic fetal monitoring based on gestational age, maternal status, and institutional protocol.
• Once stable, schedule ultrasound for fetal biometry and amniotic fluid assessment, especially in recurrent or severe HG with significant maternal weight loss.
• Discuss recurrence risk and early treatment strategies for future pregnancies.

8. Mental Health, Support & Safety

• Screen for depression, anxiety, and suicidal ideation (e.g., brief validated tool or institutional screen).
• Offer referral to: ☐ Behavioral health / psychiatry   ☐ Social work   ☐ Support organizations (e.g., HG support groups)
• Assess social determinants of health (transportation, food security, insurance coverage for antiemetics/infusions, home support).

9. Ongoing Monitoring & Discharge Planning

• Daily assessment of:
  • Symptom burden (e.g., PUQE or local score), oral intake, weight, orthostatic symptoms.
  • Electrolytes and renal function as clinically indicated.
• Adjust antiemetic regimen daily based on effectiveness and side-effects; aim for the fewest medications at effective doses.
• Criteria for discharge (individualize):
  • Able to tolerate sufficient oral intake (fluids and some solids) with manageable nausea.
  • Stable vital signs and electrolytes without continuous IV fluids.
  • Clear outpatient antiemetic plan and follow-up arranged.
• Discharge instructions:
  • Written regimen with dosing schedule for antiemetics, vitamins (including thiamine if indicated), and any acid suppression.
  • Sick-day rules (when to call triage or present to ED/L&D), red-flag symptoms, and expected course.
  • Follow-up appointments with OB/MFM and, when involved, nutrition/behavioral health.

Disclaimer

This order set is an educational template for instructional purposes only. It does not replace institutional protocols, national guidelines (e.g., ACOG, RCOG), or consultation with maternal–fetal medicine, nutrition, psychiatry, and other specialists.

Medication doses, fluid rates, and monitoring schedules must be verified against current institutional policies, pharmacy guidance, and patient-specific factors (e.g., renal/hepatic function, gestational age, comorbidities, and fetal status). For EHR implementation (e.g., Cerner/Epic), each bullet should be mapped to local orderables and adjusted to match system-specific naming, dosing defaults, and routing.

References (Selected)

1. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 189: Nausea and Vomiting of Pregnancy. Obstet Gynecol. 2018;131(1):e15–e30.
2. Nelson-Piercy C, Dean C, Shehmar M, et al. The Management of Nausea and Vomiting in Pregnancy and Hyperemesis Gravidarum (Green-top Guideline No. 69). BJOG. 2024;131(7):e1–e30.
3. Jennings LK, et al. Hyperemesis Gravidarum. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; updated 2023.
4. Maslin K, et al. Nutritional consequences and management of hyperemesis gravidarum: a narrative review. Nutr Res Rev. 2022;35(1):56–70.
5. Jansen LAW, et al. Diagnosis and treatment of hyperemesis gravidarum. CMAJ. 2024;196(14):E477–E483.
6. Erdal H, et al. Guidelines for Treatment of Hyperemesis Gravidarum and Nausea and Vomiting in Pregnancy. Int J Clin Pract. 2024;Article ID 8830099.
7. Clark SM, et al. Inpatient Management of Hyperemesis Gravidarum. (CME review, 2024; institutional protocol–based).
8. Oudman E, et al. Wernicke’s encephalopathy in hyperemesis gravidarum: a systematic review. Eur J Obstet Gynecol Reprod Biol. 2019;236:84–93.