Hyperemesis Gravidarum

Hyperemesis gravidarum (HG) is a condition in which a pregnant woman experiences extreme and prolonged nausea and vomiting throughout her pregnancy. Frequent vomiting and nausea can cause women to lose more than 5% of their body weight and cause dehydration and vitamin and mineral deficiencies.

Last Updated: February 25, 2024

Hyperemesis gravidarum affects only a small percentage of pregnant women (around 0.5 to 2%). It typically develops before the 20th week of pregnancy, between the fourth and tenth. Most people with HG get a resolution of their symptoms by the 20th week of pregnancy.


It is unclear what causes hyperemesis gravidarum. However, many circumstances may cause this condition. Changes in hCG and estrogen levels may be a factor. hCG levels peak in the first trimester, causing hyperemesis. Estrogen levels rise early in pregnancy and fall later, mirroring nausea and vomiting. Second, in the gastrointestinal system, pregnancy hormones relax the lower esophageal sphincter. This increases pregnancy-related gastroesophageal reflux disease (GERD) symptoms, including nausea. Lastly, women with a family history of hyperemesis gravidarum may also have an increased risk of developing the condition themselves.

Hyperemesis gravidarum is more common in the first trimester of pregnancy. If a woman is pregnant and vomits, she may have hyperemesis gravidarum. The following are common characteristics of HG:

  • Vomiting more than thrice or four times daily.
  • Losing more than 10 pounds because of persistent vomiting
  • Frequent fainting from dizziness
  • Starting to feel dehydrated.

HG is mainly a clinical diagnosis. Dehydration (as shown by ketonuria or electrolyte abnormalities) and weight loss (the most commonly cited marker for this is the loss of at least five percent of the patient's pre-pregnancy weight) due to vomiting are required for a diagnosis of hyperemesis gravidarum in pregnant women without another underlying pathological cause for vomiting.

Urinalysis for ketonuria and specific gravity, with a full blood count and electrolyte examination, should be part of the evaluation. Dehydration can cause hemoconcentration, leading to an increase in hemoglobin or hematocrit. Increases in serum creatinine and blood urea nitrogen and a decrease in glomerular filtration may be indicators of acute kidney injury caused by severe dehydration. Long periods of vomiting and decreased oral fluid intake can affect electrolyte levels, including potassium, calcium, magnesium, sodium, and bicarbonate.



Non-drug treatments should be tried first, like switching the patient's prenatal vitamins to folic acid supplements only, giving ginger supplements as needed, and putting on acupressure wristbands. If the patient's symptoms are severe, vitamin B6 (pyridoxine) and doxylamine should be used as first-line pharmacologic therapy. There are three ways to take medicine: with pyridoxine and doxylamine three or four times a day, with pyridoxine and doxylamine up to four times a day, or with pyridoxine and doxylamine up to two times a day.

Even though there is no known way to stop hyperemesis gravidarum from happening, the following steps might help prevent HG from worsening:

  • Eating little and frequent meals.
  • Eating bland foods.
  • Iron supplements should not be taken until the nausea subsides.
  • A doctor or nurse may suggest using a pressure-point wristband, vitamin B6, and ginger.



Jennings LK, Mahdy H. Hyperemesis Gravidarum. [Updated 2022 Sep 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532917/


Cleveland Clinic (2022). Hyperemesis Gravidarum (Severe Nausea & Vomiting During Pregnancy). Retrieved November 11, 2022, from https://my.clevelandclinic.org/health/diseases/12232-hyperemesis-gravidarum-severe-nausea--vomiting-during-pregnancy


Rare Diseases.Org (2022). Hyperemesis Gravidarum. Retrieved November 11, 2022, from https://rarediseases.org/rare-diseases/hyperemesis-gravidarum/

Last Updated: February 25, 2024