Understanding Hyperemesis Gravidarum: Severe Nausea and Vomiting in Pregnancy
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What Is Hyperemesis Gravidarum?
Hyperemesis gravidarum is the clinical term for severe nausea and vomiting of pregnancy. [1] It is distinguished from standard morning sickness by its intensity and the presence of complications like losing more than 5% of pre-pregnancy weight and severe dehydration. [1] While the exact cause is unknown, it is strongly linked to rapidly rising hormone levels, particularly human chorionic gonadotropin (HCG). [1]
What the research says
HG is linked to a higher risk of some placenta-related complications, but the evidence is uncertain. A systematic review and meta-analysis of 23 studies found that women with HG tended to have more preterm deliveries (OR 1.35, 95% CI 1.13–1.61), preeclampsia (OR 1.18, 95% CI 1.03–1.35), small-for-gestational-age babies (OR 1.24) and low birth weight (OR 1.35). The authors rated the evidence as very uncertain. (Moberg et al., BMC Pregnancy Childbirth, 2023) [3]
Having HG once raises the chance of having it again. In a study of 93,444 patients with two successive pregnancies, HG occurred in the second pregnancy in 23.8% of those who had it in the first, versus 3.4% of those who did not (adjusted relative risk 8.20, 95% CI 7.52–8.94). (Fassett et al., Reprod Sci, 2023) [4]
Ondansetron, a prescription anti-nausea drug used in severe cases, was not linked to birth defects overall. A meta-analysis of 20 observational studies found no association between ondansetron use in pregnancy and any congenital malformations (OR 1.03, 95% CI 0.98–1.09), although the authors called for more research on dose and timing. (Cao et al., Front Pharmacol, 2022) [5]
Key Takeaways
Feature | Morning Sickness | Hyperemesis Gravidarum (HG) |
Severity | Mild to moderate nausea/vomiting | Extreme, persistent nausea/vomiting [1] |
Weight Loss | None or minimal [1] | Over 5% of pre-pregnancy weight [1] |
Dehydration | Rare [1] | Common and often severe |
Duration | Usually ends by week 12-14 | Can last months or until delivery [1] |
Treatment | Medications, IV fluids, hospitalization [1] | |
Daily Impact | Usually allows for normal activities | Often debilitating; prevents daily tasks |
What is hyperemesis gravidarum?
Hyperemesis gravidarum is a much more serious condition than common morning sickness, with severe vomiting in pregnancy that prevents keeping food and liquids down. [1] It is a condition where the body's reaction to pregnancy hormones becomes overwhelming, leading to a cycle of vomiting that prevents the retention of food and liquids.
Morning Sickness vs. HG
It is crucial to differentiate between the two:
Morning Sickness: Occasional nausea, some vomiting, but the ability to keep most food down. It typically peaks around week 9 and fades by the second trimester.
Hyperemesis Gravidarum: Vomiting more than three times a day, inability to keep any fluids down, and severe fatigue. [1] It can lead to fainting, headaches, and confusion due to electrolyte imbalances.
What are the symptoms and warning signs of hyperemesis gravidarum?
The symptoms of HG are often debilitating and go far beyond simple discomfort.
Persistent Vomiting: More than three episodes daily. [1]
Severe Dehydration: Signs include dark urine, infrequent urination, and extreme thirst.
Weight Loss: A loss of 5% or more of total body weight. [1]
Neurological Symptoms: Dizziness, lightheadedness, fainting, or confusion. [1]
Physical Signs: Rapid heart rate, low blood pressure, and in severe cases, jaundice (yellowing of the skin). [1]
What causes hyperemesis gravidarum, and who is at risk?
The exact trigger for HG is not fully understood, but medical experts point to hormonal shifts as the primary driver. [1]
HCG Levels: Human chorionic gonadotropin peaks around week 10, coinciding with the most severe HG symptoms.
Estrogen: Increased estrogen levels are also believed to contribute to nausea. [1]
Genetics: A family history of HG increases a person's risk. [1]
Prior History: If you had HG in a previous pregnancy, you are at a much higher risk of experiencing it again. [1] [4]
Multiple Pregnancy: Carrying twins or triplets leads to higher hormone levels and a greater risk of HG. [1]
What complications can hyperemesis gravidarum cause?
Hyperemesis gravidarum complications stem from malnourishment and fluid loss and can include preterm birth, low birth weight, liver and kidney stress and esophageal damage.
How is hyperemesis gravidarum diagnosed?
Healthcare providers diagnose HG through a combination of physical exams and laboratory tests. [1]
Weight Tracking: Monitoring weight loss relative to pre-pregnancy levels. [1]
Urine Analysis: Checking for ketones, which indicate the body is breaking down fat for energy instead of carbohydrates.
Blood Tests: Evaluating electrolyte levels and kidney/liver function.
Ultrasound: To check for multiples or other conditions like gestational trophoblastic disease (GTD). [1]
How is hyperemesis gravidarum managed and treated?
Treatment is tailored to the severity of the symptoms and the patient's ability to tolerate oral intake.
Mild to Moderate Cases
Severe Cases
Prescription Medications: Stronger anti-emetics like promethazine or ondansetron. [1]
IV Rehydration: Intravenous fluids to restore electrolytes and hydration. [1]
Nutritional Support: In extreme cases, tube feeding or total parenteral nutrition (TPN) may be necessary to ensure both the parent and fetus receive adequate nutrients. [1]
What is the outlook and recovery for hyperemesis gravidarum?
The good news is that HG almost always resolves immediately after delivery. While the journey can be physically and emotionally exhausting, most individuals who receive proper medical care deliver healthy babies. [1]
Conclusion
Hyperemesis gravidarum is a serious condition that requires medical intervention and support. It is not something that can be "toughed out" with simple crackers. If you are unable to keep fluids down or are losing weight during pregnancy, contact your healthcare provider immediately.
Frequently Asked Questions
How is HG different from regular morning sickness?
HG involves severe, persistent vomiting that leads to weight loss and dehydration, whereas morning sickness is milder and doesn't cause these complications. [1]
When does hyperemesis gravidarum usually start?
Symptoms typically begin around the 6th week of pregnancy. [1]
Can HG harm my baby?
If treated, HG usually doesn't affect the baby. [1] Untreated, it can lead to low birth weight or preterm birth. [1]
What is the most common cause of HG?
While the exact cause is unknown, it is strongly linked to high levels of the pregnancy hormone HCG. [1]
Will I have HG in every pregnancy?
Not necessarily, but the risk is clearly higher after an affected pregnancy. [1] [4] Published recurrence rates vary widely, from about 15% to over 80% depending on the population studied [6], and a large US study found HG in the next pregnancy in 23.8% of women who had it before. [4]
Can HG last the entire pregnancy?
Yes, while it often improves after the first trimester, some people experience symptoms until delivery. [1]
What foods are best for HG?
Bland, dry foods like crackers, toast, white rice, and plain potatoes are usually tolerated best.
Is ginger effective for HG?
It can help with mild nausea, but it is often insufficient for severe HG symptoms.
What are "ketones" in urine?
Ketones are chemicals produced when the body burns fat for energy because it isn't getting enough sugar from food.
Can I take medication for HG?
Yes, there are several safe medications, including Vitamin B6, doxylamine, and prescription anti-nausea drugs. [1] [2]
What is IV therapy for HG?
It involves delivering fluids and electrolytes directly into a vein to treat dehydration.
Can HG cause depression?
The debilitating nature of HG can significantly impact mental health, leading to anxiety or depression.
Does HG affect twins more often?
Yes, carrying multiples increases hormone levels, which increases the risk of HG. [1]
Can HG cause tooth decay?
Yes, frequent vomiting exposes teeth to stomach acid, which can erode enamel.
What is Wernicke-Korsakoff syndrome?
A rare but serious neurological condition caused by a severe deficiency of Vitamin B1 (thiamine) due to prolonged vomiting.
Can HG be treated at home?
Mild cases can, but severe dehydration always requires professional medical intervention.
Is HG a "high-risk" pregnancy?
Yes, it is usually managed as a high-risk condition due to the potential for dehydration and malnutrition. [1]
Does HG mean I'm having a girl?
Some studies suggest a slightly higher incidence of HG with female fetuses due to higher HCG levels, but it occurs with both sexes.
Can I work while having HG?
Many people find it impossible to work during the peak of HG due to extreme fatigue and constant vomiting.
What is tube feeding?
A flexible tube inserted through the nose into the stomach to provide liquid nutrition when someone cannot eat.
How much weight loss is concerning in HG?
Losing more than 5% of your pre-pregnancy weight is a key diagnostic criterion for HG.
Can HG cause fainting?
Yes, dehydration and low blood pressure from HG can lead to syncopal (fainting) episodes.
Is HG more common in first-time pregnancies?
Yes, being pregnant for the first time is a known risk factor. [1]
Can stress cause HG?
No, HG is a biological condition, though stress can certainly make the experience more difficult to manage.
What is HCG?
Human chorionic gonadotropin, a hormone produced by the placenta during pregnancy.
Can HG cause jaundice?
In very severe, untreated cases, liver stress can lead to a yellowing of the skin and eyes.
Does HG affect the placenta?
HG itself doesn't affect the placenta, but severe malnutrition can impact how the placenta supports the fetus.
How often should I pee if I'm hydrated?
If you are peeing less than 3-4 times a day or the urine is very dark, you are likely dehydrated.
Can I take Unisom for HG?
Doxylamine (the active ingredient in Unisom) is often prescribed alongside Vitamin B6 for pregnancy nausea. [1]
What is TPN?
Total Parenteral Nutrition: delivering all necessary nutrients through an IV, bypassing the digestive system. [1]
Can HG cause a rapid heart rate?
Yes, tachycardia is a common sign of dehydration and electrolyte imbalance.
Are there support groups for HG?
Yes, organizations like the HER Foundation provide resources and support for those suffering from HG.
Can HG lead to early labor?
Severe malnutrition and dehydration are known triggers for preterm contractions.
Does HG affect the baby's brain development?
If treated and managed, the baby's development is usually normal.
Can I use acupressure for HG?
Pressure-point wristbands can help some people with mild nausea but are rarely enough for HG.
What is the "spit" symptom in HG?
Ptyalism, or excessive salivation, is a common and unpleasant symptom that often accompanies HG.
Can HG cause blood in vomit?
Yes, frequent retching can cause small tears in the esophagus (Mallory-Weiss tears).
Is HG related to motion sickness?
People with a history of motion sickness are at a higher risk for developing HG. [1]
Can HG be prevented?
It cannot be prevented [1], but early medical intervention can stop symptoms from becoming life-threatening.
Does HG go away immediately after birth?
For the vast majority of people, the nausea disappears almost the moment the baby (and placenta) are delivered.
Can HG affect future fertility?
No, HG does not impact your ability to get pregnant again.
What is the peak week for HG?
Symptoms often peak around week 9 to 12 when HCG levels are at their highest.
Can HG cause low blood pressure?
Yes, dehydration reduces blood volume, leading to hypotension.
Is HG more common in older mothers?
Age is not a primary risk factor; genetics and hormone sensitivity are more significant.
Can HG cause a metallic taste in the mouth?
Yes, hormonal changes and dehydration can alter the sense of taste.
What is the "bland diet" for HG?
Often called the BRAT diet (Bananas, Rice, Applesauce, Toast), it focuses on easy-to-digest foods.
Can HG cause skin problems?
Severe dehydration can lead to very dry, inelastic skin.
Is HG common?
It is relatively rare, affecting about 0.5% to 2% of pregnancies.
Can HG cause confusion?
Yes, severe electrolyte imbalances and dehydration can lead to mental fog or confusion.
Should I see a specialist for HG?
A regular OB/GYN can manage most cases, but severe HG may require a Maternal-Fetal Medicine (MFM) specialist.
References
Cleveland Clinic. Hyperemesis Gravidarum. Cleveland Clinic. Accessed October 18, 2026. https://my.clevelandclinic.org/health/diseases/12232-hyperemesis-gravidarum
ACOG Committee on Practice Bulletins—Obstetrics. ACOG Practice Bulletin No. 189: Nausea and vomiting of pregnancy. Obstet Gynecol. 2018;131(1):e15-e30. PMID: 29266076. https://doi.org/10.1097/AOG.0000000000002456
Moberg T, Van der Veeken L, Persad E, et al. Placenta-associated adverse pregnancy outcomes in women experiencing mild or severe hyperemesis gravidarum - a systematic review and meta-analysis. BMC Pregnancy Childbirth. 2023;23(1):375. PMID: 37226133. https://doi.org/10.1186/s12884-023-05691-6
Fassett MJ, Peltier MR, Lopez AH, et al. Hyperemesis gravidarum: risk of recurrence in subsequent pregnancies. Reprod Sci. 2023;30(4):1198-1206. PMID: 36163577. https://doi.org/10.1007/s43032-022-01078-8
Cao X, Sun M, Yang Q, et al. Risk of abnormal pregnancy outcomes after using ondansetron during pregnancy: a systematic review and meta-analysis. Front Pharmacol. 2022;13:951072. PMID: 36120333. https://doi.org/10.3389/fphar.2022.951072
Nurmi M, Rautava P, Gissler M, et al. Recurrence patterns of hyperemesis gravidarum. Am J Obstet Gynecol. 2018;219(5):469.e1-469.e10. PMID: 30121224. https://doi.org/10.1016/j.ajog.2018.08.018
Medical disclaimer
This guide is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read here.
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