EM@3AM – Hyperemesis Gravidarum

Author: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 28-year-old female, G2P1 at 7 weeks gestation, is brought to the ED for recurrent nausea and vomiting for several weeks. She is mildly tachycardic with dry oral mucosa. Her primary doctor sent her to the ED for treatment and further evaluation.  She has lost close to 8 lb over this past time period.

What is the patient’s diagnosis? What’s the next step in your evaluation and treatment?

Answer: Hyperemesis Gravidarum

Definition: Nausea and vomiting in the first 12 weeks of pregnancy with weight loss (>5%), ketonuria, electrolyte abnormalities (hypokalemia, alkalosis from loss of hydrochloric acid), and dehydration (high urine specific gravity) that are unresponsive to dietary modifications and medications (1-3).

Nausea affects over 75% of pregnant patients at some point (with vomiting as well in 50%), but 0.3-2% of patients will be diagnosed with hyperemesis gravidarum (1-5).

Complications: Electrolyte derangements (hypochloremic, hypokalemic metabolic alkalosis/contraction alkalosis & ketonemia), hypovolemia, low-birth weight infant.

Association with preeclampsia, eclampsia, HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), and acute fatty liver of pregnancy (AFLP) (1-3).

Evaluation: VS/PE assessment of volume status. Evaluate closely for elevated BP. Labs: CBC, BMP, ketones, UA.  If concern for other pathology, consider LFTs and lipase. Unless previously performed, obtain transvaginal vs. transabdominal US to assess for molar pregnancy/multiple gestation. 

Red Flags: Onset of nausea and vomiting over 8 weeks after the LMP. Fever, abdominal pain, and headache are atypical in hyperemesis gravidarum.

Treatment: Fluid resuscitation => D5NS or D5LR until ketonuria clears + antiemetics (ondansetron 4mg IV, pregnancy class B; vs. metoclopramide 10 mg IV or promethazine 25 mg IV, pregnancy class C) (1-3,5-7). 


– Discharge if PO tolerant with corrected electrolyte imbalances demonstrating reversal of ketonuria.  All patients discharged to home should be given an antiemetic (Vitamin B6 + doxylamine or Ginger) and scheduled for OB follow-up.

– Admit patients who remain PO intolerant after fluid resuscitation and electrolyte repletion or unclear etiology of vomiting (5-7). 

Key PointsHyperemesis occurs within the first trimester of pregnancy.  Diagnosis includes weight loss, ketonuria, electrolyte abnormalities, N/V.  BP assessment should be performed for all patients presenting outside of the first trimester, as recurrent emesis in the setting of hypertension may be a sign of pre-eclampsia.  If abdominal pain is present, consider other emergent causes. Ectopic and molar pregnancy must always be considered.  Treatment includes volume/glucose repletion, clearing of ketones, and antiemetics.

This post is sponsored by www.ERdocFinder.com, a supporter of FOAM and medical education, who with their sponsorship are making FOAM material more accessible to emergency physicians around the world.

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Further Reading:



  1. Current Diagnosis and Treatment Emergency Medicine 7e, Chapter 38. Obstetric and Gynecological Emergencies and Rape. Ryan Tucker, MD; Melissa Platt, MD
  2. Goodwin TM. Hyperemesis gravidarum. Obstet Gynecol Clin North Am 2008;35(3):401–417 [PubMed: 18760227].
  3. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 153: Nausea and vomiting of pregnancy. Obstet Gynecol. 2015 Sep;126(3):e12–24.
  4. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide 8e.  Chapter 99: Comorbid Disorders in Pregnancy, Lori J. Whelan
  5. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide 8e. Chapter 98: Ectopic Pregnancy and Emergencies in the First 20 Weeks of Pregnancy, Heather A. Heaton.
  6. Badell ML, Ramin SM, Smith JA. Treatment options for nausea and vomiting during pregnancy. Pharmacotherapy 2006; 26:1273.
  7. McParlin C, O’Donnell A, Robson SC, et al. Treatments for Hyperemesis Gravidarum and Nausea and Vomiting in Pregnancy: A Systematic Review. JAMA 2016; 316:1392.

2 thoughts on “EM@3AM – Hyperemesis Gravidarum”

  1. Please don’t forget to give thiamine. Women with hyperemesis are nutritionally stressed and there are many cases of Wernike’s encephalopathy provoked by the glucose loading given to clear ketones

    1. Great point! Thiamine can prevent significant complications in these patients to include Wernicke’s. A daily prenatal vitamin is vital if discharge is considered.

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