What is Hyperemesis Gravidarum?
Hyperemesis gravidarum (HG) is a severe and potentially debilitating form of nausea and vomiting during pregnancy. While mild to moderate nausea and vomiting, often referred to as “morning sickness,” is common in early pregnancy, hyperemesis gravidarum represents the extreme end of the spectrum. It affects approximately 0.3% to 2% of pregnant individuals and can have significant physical, psychological, and social consequences. Prompt diagnosis and appropriate management are crucial to ensure maternal and fetal well-being.
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Table of Contents
Definition and Differentiation of Hyperemesis Gravidarum
Hyperemesis gravidarum is typically defined as persistent, severe nausea and vomiting during pregnancy that leads to dehydration, electrolyte imbalances, weight loss of more than 5% of pre-pregnancy weight, and ketosis.
It is important to distinguish HG from normal pregnancy-related nausea, which does not usually result in such serious metabolic consequences or require hospitalization.
Normal Pregnancy-Related Nausea (Morning Sickness)
This typically begins around the 6th week of gestation, peaking around the 9th week, and often resolves by the end of the first trimester. It is usually manageable with dietary changes and lifestyle modifications. Women remain well-hydrated, can maintain some oral intake, and continue daily activities with minimal interruption.
Hyperemesis Gravidarum (HG)
HG is a severe condition characterized by persistent, intractable vomiting, significant weight loss, dehydration, and electrolyte imbalances. It often requires hospitalization and medical treatment such as intravenous fluids, antiemetic medications, and nutritional support. It may persist beyond the first trimester and sometimes throughout pregnancy.
| Feature | Morning Sickness | Hyperemesis Gravidarum (HG) |
|---|---|---|
| Onset | 5–6 weeks gestation | 5–6 weeks gestation (can be earlier) |
| Peak | 9–12 weeks | Varies; often peaks early and persists longer |
| Duration | Usually resolves by 12–14 weeks | Can persist beyond 20 weeks or entire pregnancy |
| Severity of Vomiting | Mild to moderate | Severe, persistent, uncontrollable |
| Weight Loss | Minimal or none | >5% of pre-pregnancy weight |
| Hydration Status | Usually remains hydrated | Dehydration common; requires IV fluids |
| Ketosis | Absent | Present (from prolonged fasting) |
| Impact on Daily Activities | Mild interference | Severe disruption; may require hospitalization |
| Treatment | Lifestyle and dietary changes | Medical therapy: IV fluids, antiemetics, nutritional support |
While morning sickness is a common and often benign part of early pregnancy, hyperemesis gravidarum is a serious condition that demands prompt medical attention. If you are unsure, please consult your doctor.(alert-passed)
Causes and Risk Factors
The exact cause of HG remains uncertain, but several contributing factors have been identified. Elevated levels of human chorionic gonadotropin (hCG), a hormone produced by the placenta, have been strongly associated with HG. This is supported by the fact that HG tends to occur more frequently in molar pregnancies and multiple gestations—conditions with high hCG levels.
Other contributing factors include:
✔ Hormonal changes (e.g., increased estrogen and progesterone)
✔ Gastrointestinal changes, such as delayed gastric emptying
✔ Genetic predisposition (family history of HG)
✔ Psychological factors, though now considered more a result than a cause
✔ Previous history of HG in prior pregnancies
✔ Obesity, multiple pregnancies, or gestational trophoblastic disease
It is important to remember that HG is a real medical condition and is not a result of a pregnant person's psychological state or a lack of coping skills.(alert-warning)
Types of Hyperemesis Gravidarum Based on Severity
Hyperemesis Gravidarum (HG) presents with varying degrees of severity, and healthcare providers often classify it into types based on symptom intensity, level of dehydration, nutritional status, and impact on daily functioning. Recognizing the severity helps guide appropriate management and interventions.
Mild Hyperemesis Gravidarum
Mild HG is characterized by nausea and vomiting that, while distressing, does not result in significant weight loss, dehydration, or electrolyte imbalance. Patients with mild HG can usually maintain oral intake and hydration. Symptoms may be manageable with lifestyle adjustments, dietary modifications, and occasional use of oral antiemetics. Hospitalization is generally not required.
Moderate Hyperemesis Gravidarum
Moderate HG involves more frequent or intense nausea and vomiting, often accompanied by moderate weight loss (usually <5–10% of pre-pregnancy weight) and signs of mild dehydration. Oral intake becomes increasingly difficult, and patients may require antiemetic medications, vitamin supplementation (e.g., thiamine), and outpatient intravenous fluids. Close monitoring of symptoms is necessary to prevent further progression.
Severe Hyperemesis Gravidarum
Severe HG is marked by intractable vomiting, significant weight loss (>10% of pre-pregnancy weight), pronounced dehydration, and electrolyte imbalances (such as hypokalemia or metabolic alkalosis). Patients with severe HG are often unable to tolerate oral intake and may exhibit ketonuria, abnormal liver enzymes, or nutritional deficiencies. Hospitalization is usually required for intravenous hydration, electrolyte replacement, antiemetic therapy, and sometimes enteral or parenteral nutrition.
It is important to seek medical attention if you are experiencing symptoms of HG, as it can lead to serious complications for both the mother and the baby.
Signs and Symptoms of Hyperemesis Gravidarum (HG)
Hyperemesis Gravidarum (HG) is a severe form of nausea and vomiting during pregnancy that goes beyond typical morning sickness. It can lead to serious complications such as dehydration, weight loss, and electrolyte imbalances if not properly managed.
1. Persistent and Severe Nausea and Vomiting
The hallmark symptom of HG is unrelenting, intense nausea often accompanied by frequent vomiting that may occur multiple times a day. Unlike the nausea of typical pregnancy (morning sickness), HG symptoms do not subside after the first trimester in many cases and may persist throughout the pregnancy. Vomiting may occur independent of food intake, and in some women, even the smell or thought of food may trigger episodes.
2. Weight Loss
A distinguishing sign of HG is significant weight loss—often more than 5% of the woman’s pre-pregnancy weight. This weight loss is due to both reduced nutritional intake and fluid loss through vomiting. Persistent caloric deficit can quickly deplete energy reserves and compromise maternal health.
3. Dehydration
Due to ongoing vomiting and limited oral intake, dehydration is a common and serious symptom. Signs may include dry mouth, dry skin, decreased urination, dark yellow urine, dizziness, and tachycardia (rapid heartbeat). Severe dehydration may require hospitalization for intravenous fluid administration.
4. Electrolyte Imbalances
Frequent vomiting leads to the loss of stomach acids and electrolytes, particularly potassium (hypokalemia), sodium (hyponatremia), and chloride. These imbalances can result in symptoms such as muscle weakness, confusion, palpitations, and in severe cases, cardiac arrhythmias or metabolic disturbances.
5. Ketonuria and Acidosis
When the body is not receiving adequate calories, it begins to break down fat for energy, producing ketones. These can be detected in the urine (ketonuria), which is a marker of starvation. This condition contributes to metabolic acidosis, making the patient feel even more nauseated, creating a vicious cycle.
6. Fatigue and Weakness
Due to the combination of malnutrition, dehydration, and poor sleep, patients with HG frequently report extreme fatigue and physical weakness. They may struggle to perform daily tasks, and their overall quality of life may significantly decline.
7. Hypotension and Tachycardia
Low blood pressure (hypotension) and increased heart rate (tachycardia) are often seen as the body attempts to compensate for volume loss caused by dehydration. These symptoms can also lead to dizziness or fainting, especially when standing up (orthostatic hypotension).
8. Other Symptoms
✔ Hypersalivation (ptyalism) – Some women with HG experience excessive salivation, which can worsen nausea.
✔ Headaches and lightheadedness – Often due to dehydration or electrolyte disturbances.
✔ Irritability and depression – The prolonged discomfort and physical toll of HG can contribute to mood disturbances, including anxiety and depression.
🔸When to Seek Medical Attention?
Women experiencing persistent vomiting, weight loss, inability to eat or drink, signs of dehydration, or dark-colored urine during pregnancy should seek medical attention promptly. Early intervention can prevent complications and improve maternal and fetal outcomes.
Complications of Hyperemesis Gravidarum (HG)
Hyperemesis Gravidarum (HG) can lead to serious complications for both the mother and the fetus if not recognized and treated early.
A. Maternal Complications
If not treated appropriately, HG can lead to various maternal health complications:
1. Nutritional Deficiencies: Prolonged vomiting can lead to severe nutritional deficiencies, especially of vitamins and minerals like folate, iron, and vitamin B1 (thiamine). Thiamine deficiency may cause Wernicke's encephalopathy, a life-threatening neurological disorder characterized by confusion, ataxia, and eye movement abnormalities.
2. Electrolyte and Metabolic Disturbances: Electrolyte imbalances such as hypokalemia, hyponatremia, and hypochloremia can lead to cardiac arrhythmias, muscle cramps, confusion, and seizures in severe cases.
3. Dehydration and Renal Impairment: Persistent vomiting without adequate fluid replacement may result in severe dehydration, reduced renal perfusion, and potentially acute kidney injury.
4. Psychological Distress: The persistent nature of symptoms, frequent hospital visits, and inability to eat or perform daily activities can lead to depression, anxiety, and a sense of isolation. HG is associated with significant mental health burdens.
5. Mallory-Weiss Tears and Esophageal Injury: Forceful vomiting may cause tears in the esophagus (Mallory-Weiss tears), leading to hematemesis (vomiting blood). Gastric ulcers or esophagitis may also occur.
6. Deep Vein Thrombosis (DVT): Prolonged immobility and dehydration may increase the risk of venous thromboembolism, particularly in patients who are hospitalized for extended periods.
B. Fetal Complications
Severe and untreated HG may also negatively impact fetal development:
1. Low Birth Weight: Due to maternal malnutrition and inadequate gestational weight gain, babies born to mothers with HG are at increased risk of low birth weight, which can impact long-term health and development.
2. Preterm Birth: HG increases the risk of preterm delivery, especially in severe cases requiring repeated hospitalizations or nutritional support. This raises concerns for neonatal respiratory and developmental issues.
3. Small for Gestational Age (SGA): Babies may be classified as SGA due to intrauterine growth restriction (IUGR) resulting from placental insufficiency linked to maternal malnutrition.
4. Fetal Neurodevelopmental Risk: Although data are limited, some studies suggest that severe maternal malnutrition during pregnancy may have long-term consequences for fetal brain development, especially if sustained through the second trimester.
5. Miscarriage: While not directly caused by HG, the physical stress and metabolic complications associated with untreated or severe HG may increase the risk of spontaneous miscarriage in some cases.
Diagnosis of Hyperemesis Gravidarum
Hyperemesis Gravidarum (HG) is a diagnosis of exclusion, meaning it is established after ruling out other causes of persistent vomiting during pregnancy. It is distinguished from typical nausea and vomiting of pregnancy (NVP) by its severity, associated weight loss, dehydration, and metabolic disturbances. Diagnosis relies on clinical history, physical examination, laboratory findings, and symptom scoring systems.
Clinical Criteria for Diagnosis
HG is typically diagnosed when the following features are present:
✔ Persistent and excessive nausea and vomiting
✔ Loss of more than 5% of pre-pregnancy body weight
✔ Signs of dehydration (e.g., dry mucous membranes, hypotension, tachycardia)
✔ Ketonuria (presence of ketones in the urine)
✔ Electrolyte imbalances (e.g., low potassium, sodium, chloride)
✔ No other underlying cause for vomiting (e.g., gastrointestinal or endocrine disorder)
A. Medical History
During the medical history, the healthcare provider will ask the patient about their symptoms, including the severity and duration of nausea and vomiting, any associated symptoms such as dizziness or fainting, and any previous history of nausea and vomiting during pregnancy. The provider will also ask about the patient's medical history, including any previous pregnancies, medical conditions, medications, and allergies.
B. Clinical Examination
The physical examination will include vital signs such as blood pressure, heart rate, and temperature, as well as a general assessment of the patient's overall health. The provider will also check for signs of dehydration, including dry mouth, decreased urine output, and low blood pressure.
C. Differentiating HG from Normal Pregnancy Nausea
Unlike typical morning sickness, which is mild and self-limiting, HG causes functional impairment and requires medical intervention. It can lead to hospitalization, IV fluid replacement, and nutritional therapy.
D. Laboratory and Diagnostic Tests
In addition to the clinical symptoms, laboratory tests may be ordered to assess for electrolyte imbalances, dehydration, and liver function abnormalities.
1. Blood tests: Blood tests can be used to assess for electrolyte imbalances, liver function abnormalities, and nutritional deficiencies.
✔ Serum Electrolytes: To identify hypokalemia, hyponatremia, hypochloremia, and metabolic alkalosis
✔ Renal Function Tests: Blood urea nitrogen (BUN) and creatinine may be elevated due to dehydration
✔ Liver Function Tests: Mild elevation in transaminases is common but should be monitored for liver-related complications
✔ Thyroid Function Tests: Transient hyperthyroxinemia can be seen; important to rule out hyperthyroidism
✔ Complete Blood Count (CBC): Hemoconcentration due to dehydration may be observed. Rule out anemia or infection.
2. Urinalysis: Urinalysis can help identify signs of dehydration, electrolyte imbalances, and other metabolic disturbances. It is also used to help detect ketonuria (which indicates starvation) and to evaluate for urinary tract infection.
3. Ultrasound: An ultrasound may be performed to rule out other causes of nausea and vomiting, such as gastrointestinal disorders or multiple gestations.
It is important for pregnant women experiencing symptoms of HG to seek medical attention promptly, as early diagnosis and treatment can help prevent complications and improve outcomes for both the mother and the baby.(alert-passed)
Pregnancy-Unique Quantification of Emesis (PUQE-24) Index
To help standardize the assessment of nausea and vomiting severity, especially in research and clinical trials, the PUQE-24 scoring system is used. It quantifies symptoms over a 24-hour period.
PUQE-24 Questionnaire
The patient is asked three questions:
How long have you felt nauseated or sick to your stomach in the past 24 hours?
1 point: None
2 points: ≤1 hour
3 points: 2–3 hours
4 points: 4–6 hours
5 points: 7–9 hours
6 points: ≥10 hours
How many times have you vomited in the past 24 hours?
1 point: None
2 points: 1 time
3 points: 2–3 times
4 points: 4–5 times
5 points: 6–7 times
6 points: ≥8 times
How many times have you had retching or dry heaves in the past 24 hours?
1 point: None
2 points: 1–2 times
3 points: 3–4 times
4 points: 5–6 times
5 points: 7–8 times
6 points: ≥9 times
Interpreting PUQE-24 Scores
3–6 points: Mild NVP
7–12 points: Moderate NVP
13–15 points: Severe NVP (suggestive of HG)
This score is often used in conjunction with clinical assessment and is not diagnostic on its own, but helpful for monitoring treatment response and determining hospital admission thresholds.
Management of Hyperemesis Gravidarum (HG)
Hyperemesis Gravidarum (HG) is a severe form of nausea and vomiting during pregnancy that can lead to significant maternal and fetal complications if not managed appropriately. The primary goals of management include preventing dehydration, correcting nutritional deficiencies, controlling nausea and vomiting, and ensuring the well-being of both mother and fetus.
General Principles of HG Management
Regardless of severity, the following principles are fundamental to the management of HG:
🔹 Woman-Centered Care: The treatment plan should be developed in collaboration with the pregnant person, taking into account their symptoms, preferences, and lifestyle.
🔹 Early and Aggressive Intervention: Prompt treatment is crucial to prevent the progression of symptoms and avoid complications like dehydration, malnutrition, and electrolyte imbalances.
🔹 Exclusion of Other Causes: Before a diagnosis of HG is finalized, other potential causes for severe nausea and vomiting must be ruled out. This can include urinary tract infections, gastroenteritis, thyroid disorders, or a molar pregnancy.
🔹 Holistic Support: Management extends beyond physical treatment to include psychological and emotional support, as HG can have a profound impact on a person's mental well-being.
🔹 Multidisciplinary Team: Care for moderate to severe HG often involves a team of healthcare professionals, including obstetricians, nurses, and dietitians.
Management is guided by the severity of symptoms, generally categorized into mild, moderate, and severe.
A. Management of Mild Hyperemesis Gravidarum
Mild cases of HG can often be managed through dietary and lifestyle changes. This may include eating smaller, more frequent meals throughout the day, avoiding foods and smells that trigger nausea, drinking plenty of fluids, and getting adequate rest.
1. Dietary and Lifestyle Modifications
✔ Frequent small meals: Avoid an empty stomach. Eating bland, dry, and high-carbohydrate snacks (e.g., crackers) may help.
✔ Avoid triggers: Strong smells, spicy or fatty foods, and iron supplements may exacerbate nausea.
✔ Stay hydrated: Small, frequent sips of fluids like water, clear broth, ginger ale, or electrolyte solutions are encouraged.
✔ Rest and stress reduction: Adequate sleep and stress management may alleviate symptoms.
2. Pharmacological Management
Anti-nausea medications, which can be taken orally or administered through an injection or an IV, are a primary treatment.
✔ First-line medications such as Pyridoxine (Vitamin B6) or Doxylamine (may be combined with pyridoxine)
✔ Other options (if B6/doxylamine fails):
➧ Antihistamines: Meclizine or diphenhydramine
➧ Metoclopramide (dopamine antagonist): Prokinetic and antiemetic effect
Note: Please consult your doctor before taking any medication. Self-medication might cause harm to oneself and to the unborn baby.
It's important to note that even mild cases of HG can have a significant impact on a woman's quality of life and well-being. If left untreated, mild HG can progress to more severe symptoms, which can pose risks to both the mother and the fetus. For this reason, it's important for women experiencing any degree of nausea and vomiting during pregnancy to talk to their healthcare provider about their symptoms and develop a plan for managing them.
B. Management of Moderate Hyperemesis Gravidarum
Moderate HG is defined by more frequent vomiting, mild dehydration, and some weight loss (less than 5% of pre-pregnancy weight). At this stage, oral medications are often necessary, and if symptoms don't improve, a step-up in care is required.
1. Combination Therapy: The combination of vitamin B6 and doxylamine (an antihistamine) is a well-established first-line oral treatment.
2. Antiemetics: If the combination therapy is not effective, other antiemetics may be prescribed:
✔ Antihistamines: Diphenhydramine or promethazine can be used. These can cause drowsiness, which may be a beneficial side effect for some.
✔ Dopamine Antagonists: Metoclopramide is a common choice, but its use is generally limited to short-term treatment due to the risk of extrapyramidal side effects.
✔ Serotonin Antagonists: Ondansetron is a highly effective antiemetic, often used for moderate to severe HG. Its use in early pregnancy has been a subject of debate, and its risks versus benefits should be carefully considered with a healthcare provider.
3. Outpatient Hydration: If oral intake is insufficient to maintain hydration, a person may be given intravenous (IV) fluids in an outpatient setting, such as a day hospital or clinic. This allows for rehydration and electrolyte correction without requiring a full hospital admission.
4. Monitoring: Electrolytes, liver function, and renal function should be monitored, especially if vomiting persists.
C. Management of Severe Hyperemesis Gravidarum
Severe HG is a medical emergency characterized by intractable vomiting, significant weight loss (more than 5%), severe dehydration, ketosis, and electrolyte imbalances. Hospitalization is usually required to stabilize the pregnant person and prevent life-threatening complications.
1. Aggressive IV Rehydration and Electrolyte Correction
✔ Start with isotonic fluids (0.9% saline), often with added potassium.
✔ Give IV thiamine (100 mg daily) to prevent Wernicke's encephalopathy, especially before glucose administration.
✔ Correct electrolyte imbalances (hypokalemia, hyponatremia, hypochloremia).
2. Antiemetic Therapy
✔ Multimodal antiemetic regimen is often required:
✔ Ondansetron, promethazine, metoclopramide, or droperidol
✔ In refractory cases, methylprednisolone may be used (after 10 weeks of gestation, due to risk of orofacial clefts).
3. Nutritional Support
✔ Enteral nutrition (nasogastric or nasojejunal feeding) may be considered if oral intake is not tolerated after 72 hours.
✔ If enteral feeding fails or is contraindicated, total parenteral nutrition (TPN) may be necessary.
4. Adjunctive Therapies
✔ Acid suppression with H2-receptor antagonists (ranitidine) or proton pump inhibitors (omeprazole) to manage gastritis symptoms.
✔ Psychological support or counseling may be necessary, as HG is linked to anxiety and depression.
D. Discharge and Follow-up
✔ Once a person is stabilized, they are transitioned back to oral intake slowly and cautiously.
✔ A discharge plan is created, which includes a continued antiemetic regimen and a clear plan for follow-up care.
✔ Patients and their families are educated on the signs of returning dehydration or ketosis, and when to seek immediate medical attention.
E. Planning for Future Pregnancies
For individuals with a history of HG, pre-conception counseling is vital. Proactive management and early, aggressive treatment with antiemetics at the first sign of symptoms can significantly reduce the severity and duration of HG in a subsequent pregnancy.
Effective management of Hyperemesis Gravidarum requires early recognition, tailored treatment based on severity, and ongoing support for the mother’s physical and psychological health. Prompt intervention can reduce complications, improve maternal comfort, and support healthy pregnancy outcomes.(alert-passed)
Prognosis of Hyperemesis Gravidarum (HG)
The prognosis of Hyperemesis Gravidarum (HG) is generally favorable with timely and appropriate treatment, though it can vary based on the severity of the condition, the timing of intervention, and the presence of complications. While most women recover fully, HG can have significant short- and long-term effects on both the mother and the fetus, especially if inadequately managed.
A. Maternal Prognosis
Short-Term Outlook
In most cases, symptoms of HG begin in the first trimester, often around 4–6 weeks of gestation, and peak between 9–13 weeks. With supportive care, many women experience symptom improvement or resolution by 20 weeks. However, about 10–20% of affected women may continue to experience symptoms beyond the second trimester, and in rare cases, symptoms persist until delivery.
Women who receive early intervention typically recover well. However, severe or prolonged HG can lead to complications such as dehydration, electrolyte imbalances, nutritional deficiencies, liver dysfunction, and venous thrombosis. With aggressive treatment and monitoring, these risks can be minimized.
Long-Term Effects
While physical recovery is usually complete, psychological and emotional effects may persist. Many women report experiencing post-traumatic stress, depression, and anxiety even after delivery due to the severity of their symptoms. A history of HG also increases the likelihood of recurrence in subsequent pregnancies, with recurrence rates ranging from 50–80%.
B. Fetal Prognosis
The majority of pregnancies affected by HG result in healthy live births, especially when maternal hydration and nutrition are maintained. However, in untreated or severe cases, HG can negatively impact fetal outcomes.
Risks Associated with Poor Maternal Nutrition
Severe and prolonged vomiting may lead to maternal malnutrition, which in turn can increase the risk of low birth weight, small for gestational age (SGA) infants, and preterm birth. These risks are largely preventable with early intervention and proper nutritional support.
No Increased Risk of Congenital Anomalies
HG itself is not associated with an increased risk of birth defects, unless complicated by inadequate supplementation of essential nutrients like folate or thiamine (which can lead to conditions like Wernicke's encephalopathy in the mother).
C. Prognosis with Treatment vs. Without
When properly diagnosed and managed, the prognosis of HG is excellent. Timely rehydration, antiemetic therapy, nutritional support, and psychological care significantly improve both maternal and fetal outcomes. On the other hand, delayed or inadequate treatment can lead to serious maternal complications, increased healthcare costs, and potential fetal growth restriction or premature delivery.
D. Recurrence in Future Pregnancies
One of the most notable concerns for women who have experienced HG is the high rate of recurrence. Studies estimate that 50–80% of women will experience HG again in subsequent pregnancies. The severity may be similar or even more pronounced. Preconception counseling and early intervention in future pregnancies are essential to minimize recurrence-related complications.
E. Quality of Life Considerations
Despite a generally good physical prognosis, HG has a substantial impact on quality of life. Many women are unable to work, care for children, or perform daily activities during the illness. Postpartum, some report lingering emotional distress and hesitation about future pregnancies. Support groups and counseling can be valuable in addressing these issues and improving psychological well-being.
The prognosis of Hyperemesis Gravidarum is favorable with early recognition and comprehensive management. While maternal and fetal complications can occur, these are largely preventable with proper care. The condition often resolves during pregnancy or after delivery, but the psychological and emotional effects may require long-term attention. As HG has a high recurrence risk, proactive planning and preconception counseling are crucial for women with a history of this condition.(alert-passed)
