Nausea and Vomiting in Pregnancy

General Nausea and Vomiting

Patient < 20 WGA with h/o motion sickness, migraine, and nausea presents with nausea and vomiting. Symptoms are worse in the morning but last all day. Denies abdominal pain, diarrhea. No fever, abdominal pain, abdominal tenderness on exam.

  • Initial treatment

    • Start ginger 250 mg q8h and pyridoxine (vitamin B6) 50 mg q8h

    • Trial of doxylamine (Unisom Orange) 25 mg before bed; may increase to 25 mg q8h

  • Nausea and vomiting refractory to initial treatment (advance through each of the following)

    • Promethazine (Phenergan) 25 mg q4h PRN and counsel patient about risk for extrapyramidal symptoms

    • Metoclopramide (Reglan) 10 mg q6h and counsel patient about risk for promotility effects, tardive dyskinesia

    • Ondansetron (Zofran) 4 mg q8h

      • Patient < 10 WGA with severe, refractory symptoms: Patient counseled that medication benefits likely outweigh risks

      • Patient > 10 WGA: Start ondansetron if patient fails promethazine and metoclopramide

  • Counseling

    • Patient advised to avoid large, high-protein meals

    • Patient advised that acupuncture therapy is not effective

    • Patient counseled against taking OTC scopolamine due to risk of fetal deformity

    • Patient counseled that pyridoxine must be taken 3 times daily every day to be effective

    • Patient counseled that nausea and vomiting typically resolves after 20 WGA

Notes

  • Differential diagnosis includes cholecystitis, gastroenteritis, GERD, and migraine headache

  • Continue ginger, pyridoxine, and doxylamine when starting promethazine, metoclopramide, or ondansetron

  • Ondansetron

    • Pregnancy category B

    • Crosses the placenta in the first trimester but has not been shown to cause adverse events in animal studies

    • Data for fetal safety in the first trimester are conflicting, but benefits likely outweigh risks in refractory cases

 

Hyperemesis Gravidarum

Pregnant patient with h/o fetal triploidy presents with severe nausea and vomiting. Greater than 5% weight loss noted during pregnancy. Symptoms refractory to combination of ginger, pyridoxine, doxylamine, and ondansetron. Tachycardia, orthostasis, dry mucous membranes on exam.

  • Obtain CBC, CMP, TSH, U/A, beta-hCG and evaluate for hypokalemia, elevated transaminases, hyperthyroidism, ketonuria, abnormally elevated beta-hCG

  • Obtain ultrasound to evaluate for multiple gestation and rule out molar pregnancy

  • Treatment

    • > 10 WGA: Start methylprednisolone 16 mg q8h x 3 days and then taper over 2 weeks

    • Consider trimethobenzamide 300 mg q6h

    • Hypovolemia

      • Start IV fluids with thiamine for dehydration

      • Consider admission for feeding tube placement