Hyperemesis gravidarum

Background

• Simple nausea and vomiting affects 60-80% of patients during first 12wk of pregnancy
• Hyperemesis gravidarum only affects 0.3-2% of pregnancies
• Hyperemesis gravidarum has (rarely) been known to cause Wernicke's encephalopathy

Clinical Features

Pregnancy with:

• Nausea and vomiting
• Weight loss
• Volume depletion

Note: Abdominal pain is highly unusual and should prompt consideration of a different diagnosis

Differential Diagnosis

Nausea and vomiting in pregnancy

• Hyperemesis gravidarum
• Gastroenteritis
• Biliary disease
• Ectopic pregnancy
• Gastroenteritis
• Pancreatitis
• Appendicitis
• Hepatitis
• Peptic ulcer disease
• Pyelonephritis
• Acute fatty liver of pregnancy
• HELLP syndrome
• Gestational trophoblastic disease (may present with intractable vomiting)
  • Molar pregnancy
• Thyrotoxicosis (may present with intractable vomiting)

Evaluation

Workup

• Urinalysis for ketones
• Chemistry
  • May show signs of dehydration, hypokalemia
• CBC

Diagnosis

• Defined as intractable vomiting with at least 1 of following:
  • Weight loss
  • Volume depletion
  • Hypokalemia
  • Ketonemia

Note: Abdominal pain is highly unusual and should prompt consideration of a different diagnosis

Management

Rehydration

• PO fluids if able to tolerate
• IV fluid repletion (use D5NS in the setting of ketonuria)

Antiemetics

ACOG recommends a stepwise approach to nausea and vomiting in pregnancy

• Vitamin B6 10-25mg q6-8hrs
• ADD Doxylamine 12.5mg q6-8hrs
• ADD Promethazine 12.5-25mg q4hrs PO or PR
• ADD Dimenhydrinate 50mg q4-6hrs IV OR metoclopramide 5-10mg q8hrs IV OR promethazine 12.5-25mg q4hrs IV
• ADD Methylprednisolone 16mg q8hrs PO or IV for 3 days and taper to effective dose OR ondansteron 8mg (or 4mg) q12hrs IV
  • If using ondansetron, reasonable to have a discussion about claimed risks of birth defects.
  • First-trimester exposure to ondansetron was not associated with cardiac or congenital malformations but was associated with a small increased risk of oral clefts.

Medication	Pregnancy Drug Class
Vitamin B6	A
Dimenhydrinate	B
Doxylamine	A
Ondansetron	B
Metoclopramide	B
Promethazine	C

Disposition

• Discharge if clear diagnosis and able to tolerate POs
• Admit
  • Uncertain diagnosis
  • Intractable vomiting
  • Persistent ketonemia or electrolyte abnormalities after volume repletion
  • Weight loss >10% of pre-pregnancy weight

See Also

• Nausea and vomiting