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What is hyperemesis gravidarum

What is hyperemesis gravidarum

Navin Khosla NowPatientGreen tick
Updated on 28 Dec 2023

During pregnancy, many women experience nausea and vomiting, commonly known as morning sickness. Mild nausea and vomiting of pregnancy usually won’t cause harm. However, for some pregnant women, these symptoms can become severe and persistent, significantly impacting their daily lives. This condition is known as hyperemesis gravidarum (HG), and it affects approximately 1-3% of pregnancies. In this comprehensive guide, we will explore the causes, symptoms, treatment options, and potential complications of HG to provide a better understanding of this condition.

What is Hyperemesis Gravidarum?

Hyperemesis gravidarum is a condition characterized by persistent and severe nausea and vomiting during pregnancy. Unlike mild morning sickness, which tends to improve after the first trimester, HG can last throughout the entire pregnancy. It can lead to dehydration, weight loss, electrolyte imbalances, and other health complications if not properly managed. While the exact cause of HG is unknown, hormonal changes and genetic factors are believed to play a role in its development.

Symptoms of Hyperemesis Gravidarum

The symptoms of HG are more severe than regular morning sickness. Women with HG may experience prolonged and severe nausea and severe vomiting, leading to dehydration and weight loss. Other signs of HG include excessive salivation, dehydration symptoms such as thirst, fatigue, dizziness, and dark-coloured urine. It is important to differentiate between mild morning sickness and HG, as the latter requires medical attention and proper treatment.

Diagnosing Hyperemesis Gravidarum

Diagnosing HG is based on a clinical evaluation of the patient’s symptoms and medical history. Healthcare providers may assess the frequency and severity of nausea and vomiting, weight loss, and signs of dehydration. Laboratory tests, such as a complete blood count and electrolyte evaluation, may be performed to check for ketonuria and electrolyte imbalances. Ultrasounds can help rule out other conditions and determine the number of gestations.

Causes of Hyperemesis Gravidarum

While the exact causes of HG remain unknown, hormonal changes in pregnancy, particularly high levels of human chorionic gonadotropin (hCG) and estrogen are believed to contribute to the development of HG. Genetic factors may also play a role, as women with a family history of HG are more likely to experience it themselves. Additionally, risk factors such as multiple gestations and hydatidiform moles increase the risk of developing HG.

Treatment options for Hyperemesis Gravidarum

The treatment of HG aims to alleviate symptoms, prevent dehydration, and ensure adequate nutrition for both the mother and the baby. The first line of treatment includes non-pharmacological interventions, such as dietary modifications and lifestyle changes. If these measures are insufficient, medications may be prescribed. Vitamin B6, antihistamines, dopamine antagonists, and other antiemetic drugs can help control nausea and vomiting. In severe cases, hospitalization and intravenous fluids may be necessary.

Antihistamines – Cyclizine and Promethazine

Antihistamines are often first-line treatments for HG such as cyclizine and promethazine. These medications can be taken in combination with pyridoxine (Vitamin B6). Antihistamines have been found to be effective in treating nausea and vomiting in pregnancy, with no harmful defects reported in the fetus. It is important to note that these medications can cause drowsiness and should be taken under medical advice. Starting with a low dose and gradually increasing it can help minimize the drowsy effect.


Prochlorperazine, a phenothiazine drug, is another first-line medication that can be used for severe nausea and vomiting in pregnancy. Studies have shown that prochlorperazine is effective in treating HG, with no increased risk of major malformations reported. However, it can cause side effects such as drowsiness, restlessness, and occasional extrapyramidal effects. Prochlorperazine is a prescription-only medication and should be used under medical supervision.


Chlorpromazine is a first-line medication that is rarely prescribed for HG. It is usually tried after other first-line medications have been attempted. Chlorpromazine works similarly to other first-line medications and can be used in combination with them for better symptom control. However, it is important to follow medical advice and guidance when considering this medication.


Metoclopramide is often a second-line treatment option for HG. While limited information is available on its safety during pregnancy, the published data is reassuring. Metoclopramide is generally well-tolerated, but it may cause side effects such as drowsiness, restlessness, and occasional extrapyramidal effects. It is important to note that the European Medicines Agency recommends using metoclopramide for a maximum of 5 days to minimize the risk of side effects. However, this recommendation is primarily for other patient populations and not specifically for pregnant women with HG.


Originally used to treat chemotherapy-induced nausea and vomiting, ondansetron is increasingly being used for HG. Research on the safety of ondansetron during pregnancy is ongoing, but studies have shown no link to heart defects and minimal associated risk of cleft lip/palate when taken in the first 10 weeks of pregnancy. The risk is considered very small, with only a few additional cases per 10,000 births. Ondansetron is available as an oral tablet, injection, suppository, or oro-dispersal tablet. It is important to discuss the potential benefits and risks with your healthcare provider when considering ondansetron.


Steroids are often considered a third-line treatment for HG when all other measures have failed. They can be highly effective in managing severe symptoms, but most women will be able to stop taking steroids by 18-20 weeks of pregnancy. However, around 1 in 5 women may need to continue taking a low dose of steroids for the remainder of their pregnancy. While the exact mechanism of how steroids work for HG is not fully understood, they are believed to have a boosting effect on other medications. It is important to note that steroids should be used sparingly, at the lowest effective dose and for the shortest possible duration to minimize potential side effects. Some potential side effects for the pregnant person include developing gestational diabetes, an increased risk of infection, and adrenal suppression. The baby may also be monitored after delivery if the pregnant person is still taking steroids. The decision to use steroids should be based on a careful assessment of the risks and benefits, considering the severity of the symptoms and the potential harm of untreated HG.

Intravenous (IV) Fluids

Intravenous (IV) fluids play a crucial role in the management of HG, particularly in cases of severe dehydration. IV fluids help correct dehydration, provide essential nutrients, and deliver medication directly into the bloodstream when oral medications cannot be tolerated. It is important to note that relying solely on urine ketone levels to determine the need for IV fluids is not the best practice. Signs and symptoms of dehydration, such as darker urine, decreased urination, dry mouth, headaches, and weakness, should be assessed to determine the need for IV fluid rehydration. IV fluid therapy should be readily available for those with HG to prevent complications associated with dehydration.

Alternative therapies

While medication is the primary treatment approach for HG, some women may prefer to explore alternative therapies before or alongside medical interventions. It is important to note that alternative therapies may provide relief for mild symptoms but are unlikely to be sufficient for severe cases of HG. Here are a few alternative therapies that some women have found helpful:


Acupressure involves stimulating specific pressure points on the body to alleviate nausea and vomiting. One commonly targeted point is the P6 point, located three fingers breadth above the wrist. Wearing wristbands that apply pressure to this point may provide some relief. Acupressure is generally considered safe during pregnancy, but it is important to consult with a qualified practitioner and discuss any concerns with your healthcare provider.

Acupuncture and hypnotherapy

Some women have reported finding relief from HG symptoms through acupuncture and hypnotherapy. However, the effectiveness of these therapies can vary from person to person, and their use may be more expensive compared to medication. If considering these alternative therapies, it is essential to have a backup plan and seek medical advice to ensure comprehensive management of HG symptoms.


Ginger is a commonly suggested remedy for nausea and vomiting, including HG. While some small studies have suggested its effectiveness, the evidence is limited, and the purity and composition of ginger preparations can vary. A survey conducted by Pregnancy Sickness Support found that ginger was ineffective for many women with HG and could even cause unpleasant side effects. It is important to approach ginger use with caution and seek medical advice before trying it.

Potential complications of Hyperemesis Gravidarum

When left untreated, HG can lead to various complications for both the mother and the baby. Maternal complications may include weight loss, malnutrition, electrolyte imbalances, and psychological distress such as depression and anxiety. Fetal complications can arise from inadequate nutrition and may result in low birth weight, prematurity, and developmental issues. Early intervention and proper management of HG can help minimize these risks.

Impact on quality of life

Hyperemesis gravidarum can significantly impact a woman’s quality of life during pregnancy. The severity and duration of symptoms can lead to physical and emotional distress, affecting daily activities, work, and social interactions. Women with HG may experience feelings of isolation, anxiety about leaving their homes, and uncertainty about how to cope with the rest of their pregnancy. Healthcare providers must provide empathetic support and offer resources to help women navigate this challenging condition.

Coping strategies and support

Managing HG requires a comprehensive approach that includes both medical treatment and emotional support. Patients can benefit from connecting with support networks and organizations specializing in HG, such as Pregnancy Sickness Support. These resources provide valuable information, coping strategies, and opportunities to connect with others who have experienced HG. Open communication with healthcare providers, partners, family members, and friends can also contribute to emotional well-being and better management of the condition.

Planning for future pregnancies

If a woman has experienced HG in a previous pregnancy, there is a higher likelihood of experiencing it again in subsequent pregnancies. Planning and discussing the possibility of HG with healthcare providers can help prepare for future pregnancies. Exploring strategies, such as starting medication early or arranging additional support, can improve the management of HG in subsequent pregnancies.


Hyperemesis gravidarum is a severe form of nausea and vomiting during pregnancy that can have significant physical, emotional, and social impacts on women. Early recognition, proper diagnosis, and timely treatment are crucial in managing this condition and minimising its potential complications. By providing comprehensive care, support, and education, healthcare providers can help women navigate HG and ensure a healthier pregnancy for both the mother and the baby.


Medical Disclaimer

NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information in this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

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