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BASICS

Description

  • HG is intractable vomiting during pregnancy causing fluid, electrolyte, and nutritional imbalance.
  • Typically occurs 8–20 weeks gestation, peaking around week 12 and resolving by week 20.
  • Associated with elevated estrogen and hCG.
  • Affects endocrine/metabolic, gastrointestinal, and reproductive systems.

Epidemiology

  • Affects 0.5–2% of pregnancies.
  • More common in young, primiparous, nonsmoking, nonwhite women.
  • Risk factors: prior HG, diabetes, hyperthyroidism, psychiatric illness, asthma, GI disorders.

ETIOLOGY AND PATHOPHYSIOLOGY

  • Exact cause unknown.
  • Proposed factors: pregnancy hormones, hyperthyroidism, autonomic dysfunction, CNS neoplasms, liver dysfunction, Addison disease, genetics, psychological factors.
  • Increased risk with family history of HG.
  • Other associations: multiple gestations, female fetus, trisomy 21 fetus, migraines, motion sickness, Helicobacter pylori infection.

GENERAL PREVENTION

  • Dietary guidance:
  • Small, frequent meals.
  • Avoid empty or overly full stomach.
  • Avoid greasy, spicy, fatty foods.
  • Favor bland, low-fiber, high-protein snacks.

DIAGNOSIS

History

  • Persistent nausea and vomiting (>3 episodes/day).
  • Decreased urine output, fatigue, dizziness, poor appetite.

Physical Exam

  • Weight loss >5% from prepregnancy.
  • Signs of dehydration (orthostatic hypotension, ketonuria).
  • Thyroid exam.

Differential Diagnosis

  • Gastroenteritis, gastritis, reflux, peptic ulcer disease.
  • Cholelithiasis, cholecystitis, pancreatitis.
  • Pyelonephritis, appendicitis.
  • Endocrine causes: hyperparathyroidism, thyrotoxicosis.
  • H. pylori infection.
  • Anxiety.

Diagnostic Tests

  • Urinalysis: ketones, specific gravity, glucosuria.
  • TSH, free T4: transient hyperthyroidism common; evaluate overt hyperthyroidism.
  • Electrolytes, BUN, creatinine for dehydration.
  • Liver enzymes (AST/ALT) mildly elevated in ~50%.
  • Hematocrit: increased due to volume contraction.
  • Hepatitis panel to exclude viral causes.
  • Calcium for rare hyperparathyroidism.
  • Albumin for malnutrition.
  • Imaging as indicated to exclude other causes (ultrasound, MRI).

TREATMENT

General Measures

  • Correct dehydration and electrolyte imbalances.
  • IV fluids: normal saline or 5% dextrose normal saline.
  • Thiamine supplementation to prevent deficiency (PO 25–50 mg TID or IV 100 mg weekly).
  • Consider parenteral nutrition if needed.

Medications

First Line

  • Pyridoxine (Vitamin B6) 25 mg PO/IV q8h, max 200 mg/day.
  • Doxylamine succinate (12.5 mg) combined with pyridoxine (25 mg) more effective than either alone.
  • Ginger capsules 350 mg PO TID for refractory vomiting.

Second Line

  • Antihistamines: diphenhydramine, meclizine, dimenhydrinate.
  • Metoclopramide 10 mg PO q8h.
  • Promethazine 12.5 mg PO/rectal q8h.
  • Ondansetron 4–8 mg PO/IV q8h (caution: QT prolongation warning).

Others

  • Methylprednisolone 16 mg PO/IV q8h for 2–3 days, taper over 2 weeks; reserved for severe refractory cases.
  • H2 blockers (cimetidine, ranitidine) for acid reflux symptoms.

Additional Therapies

  • Rarely, enteral or parenteral nutrition required if refractory.
  • Early enteral tube feeding does not improve maternal or fetal outcomes.

COMPLEMENTARY & ALTERNATIVE MEDICINE

  • Ginger (350 mg PO q6h) may be helpful [A].
  • Acupressure bands at Neiguan point effective as adjuvant in severe cases [A].
  • Medical hypnosis shows potential, requires further study.

ONGOING CARE

Follow-Up

  • Daily weight monitoring in severe cases.
  • Monitor for ketosis, hypokalemia, acid-base disturbances.
  • Approximately 10% of patients experience symptoms throughout pregnancy.

Diet

  • Bland or liquid diet as tolerated.
  • Small frequent meals rich in carbohydrates and protein.
  • Avoid spicy and high-fat foods.

PATIENT EDUCATION

  • Address psychosocial issues, pregnancy ambivalence.
  • Encourage small frequent fluid intake.
  • Avoid foods triggering symptoms.
  • Use "wet-to-dry" diet (e.g., sherbet, broth, gelatin, dry crackers).

PROGNOSIS

  • Generally self-limited with good prognosis if weight maintained >95% prepregnancy.
  • Severe complications include hemorrhagic retinitis (50% mortality), liver damage.

COMPLICATIONS

Maternal

  • Vitamin deficiencies.
  • Dehydration and malnutrition.
  • Wernicke encephalopathy due to thiamine deficiency.
  • Coma, death in severe untreated cases.

Fetal

  • 5% maternal weight loss linked to intrauterine growth retardation, fetal anomalies.

  • Poor weight gain associated with increased risk of small for gestational age and preterm birth.

REFERENCES

  1. Maltepe C, Koren G. The management of nausea and vomiting of pregnancy and hyperemesis gravidarum—a 2013 update. J Popul Ther Clin Pharmacol. 2013;20(2):e184-e192.
  2. Boelig RC, Barton SJ, Saccone G, et al. Interventions for treating hyperemesis gravidarum. Cochrane Database Syst Rev. 2016;2016(5):CD010607.
  3. Viljoen E, Visser J, Koen N, et al. Effect and safety of ginger in treatment of pregnancy-associated nausea and vomiting: systematic review and meta-analysis. Nutr J. 2014;13:20.
  4. Adlan AS, Chooi KY, Mat Adenan NA. Acupressure for nausea and vomiting in early pregnancy: a double-blind RCT. J Obstet Gynaecol Res. 2017;43(4):662-668.
  5. Grooten IJ, Koot MH, van der Post JA, et al. Early enteral tube feeding in hyperemesis gravidarum: a RCT. Am J Clin Nutr. 2017;106(3):812-820.
  6. Heitmann K, Nordeng H, Havnen GC, et al. Burden of nausea and vomiting during pregnancy: impacts on quality of life. BMC Pregnancy Childbirth. 2017;17(1):75.
  7. Veenendaal MVE, van Abeelen AFM, Painter RC, et al. Consequences of hyperemesis gravidarum for offspring: a systematic review and meta-analysis. BJOG. 2011;118(11):1302-1313.