Hyperemesis gravidarum

Pregnancy is a time of significant physical and emotional changes for women, and while some discomfort is expected, certain conditions can greatly impact a woman's quality of life. One such condition is hyperemesis gravidarum, a severe form of morning sickness that affects a small percentage of pregnant women. Expectant mothers need to be aware of this condition, its symptoms, and when to seek medical attention to prevent potential complications.

What is Hyperemesis Gravidarum?

Hyperemesis gravidarum (HG) is a condition in pregnancy where you have severe and constant nausea and vomiting. It can cause weight loss and dehydration. HG is sometimes known as extreme morning sickness.

Hyperemesis gravidarum (HG) usually starts in the first trimester of pregnancy, around six weeks in. It can last for weeks, months, or even until birth. The symptoms can be very strong and may stop you from doing your daily activities.

Common symptoms of hyperemesis gravidarum:

• Severe nausea
• Recurrent, intractable vomiting that may occur multiple times per day and impairs oral intake.
• Losing more than 5% of your pre-pregnancy weight
• Being unable to keep food or drinks down
• Dehydration
• Dizziness or feeling lightheaded
• Urinating less than usual
• Extreme tiredness
• Fainting
• Headaches

Less common symptoms:

• Low blood pressure
• Fast heart rate
• Dry skin
• Confusion
• Jaundice (rare; may occur secondary to severe dehydration or prolonged vomiting leading to transient hepatic dysfunction).
• A rare neurological complication called Wernicke encephalopathy (due to thiamine deficiency), which may progress if untreated

The exact cause is multifactorial and not fully understood. Contributing mechanisms include elevated hCG levels, genetic predisposition, increased sensitivity to pregnancy-related hormones, and emerging evidence implicating the placenta-derived hormone GDF15 as a major driver of HG severity (Fejzo et al., 2024) 

While any pregnant woman can develop hyperemesis gravidarum, certain factors may increase your risk, including:

• A previous history of HG in past pregnancies
• Carrying twins or multiples
• Having a genetic predisposition, particularly if your mother or sister suffered from HG (suggesting the condition may run in families)
• Being prone to motion sickness

Other associated factors may include a history of migraines, motion sickness, or high sensitivity to hormonal changes. Chronic medical conditions (e.g., renal or hepatic disorders) are not established risk factors for HG itself but may worsen tolerance to vomiting (Fejzo et al., 2024).

Preventing hyperemesis gravidarum (HG) with complete certainty is not currently possible. Although there are no known methods to entirely prevent HG, some steps can be taken to potentially reduce its severity or prepare for its impact. Recurrence risk is high, with studies reporting rates of approximately 15–80% depending on diagnostic criteria and severity, but the exact recurrence probability varies across populations. Taking a multivitamin containing vitamin B6 before getting pregnant may help reduce the severity of symptoms. Early, pre-emptive use of vitamin B6 supplements and first-line medications has shown effectiveness in preventing the deterioration of HG symptoms. Maintaining a healthy diet rich in nutrient-dense foods and ensuring adequate levels of essential vitamins like thiamine (B1) may also help mitigate the severity of HG. Lifestyle changes, such as eating small, frequent meals high in protein and avoiding spicy, fatty, or oily foods, can be beneficial. However, it is crucial to note that these measures do not guarantee the prevention of HG but can assist in managing and reducing its impact. If you suspect symptoms of HG or have a history of it, consult your healthcare provider promptly.

Diagnosing hyperemesis gravidarum (HG) involves a combination of clinical evaluation, medical history, and physical examination. The healthcare provider will assess the severity of the patient's symptoms, such as severe nausea and vomiting of pregnancy that impairs their ability to eat and drink normally, affecting daily activities. These hyperemesis gravidarum symptoms typically begin between the 4th and 6th week of pregnancy and can persist throughout the first trimester or longer. Blood and urine tests may be ordered to check for dehydration, electrolyte imbalances, and ketonuria. Ketonuria may occur due to prolonged starvation, but it is not required for diagnosis; HG is diagnosed clinically based on the severity of nausea/vomiting, inability to maintain hydration/nutrition, weight loss, and functional impairment (RCOG, 2024). The provider may also perform tests to rule out other causes of nausea and vomiting, such as gastrointestinal illnesses or urinary tract infections. An ultrasound may be used to determine if the patient is carrying multiple fetuses or has other conditions like trophoblastic disease, which can also cause HG. Once diagnosed, appropriate hyperemesis gravidarum treatment can be initiated to manage the condition and alleviate the debilitating morning sickness in pregnancy.

Managing moderate to severe cases of nausea and vomiting requires medical intervention. Below are key treatment approaches incorporating medications:

1. Prescription Medication

• Doxylamine + Vitamin B6 (Pyridoxine) is often the first-line treatment, helping to reduce nausea and vomiting (RCOG, 2024).
• If symptoms persist, stronger medications such as Promethazine, Metoclopramide, or Ondansetron may be required.

These medications can be administered orally, via injection, or through an IV, depending on the severity of symptoms.

2. IV Fluids

• In cases of dehydration, intravenous (IV) fluids help restore fluid balance and essential nutrients.
• Thiamine supplementation (100 mg IV or oral) should be given before administering IV dextrose or carbohydrate-containing fluids to prevent Wernicke encephalopathy (RCOG, 2024).

3. Tube Feeding

• Enteral feeding (nasogastric or nasojejunal tube) may be considered in refractory cases when oral intake cannot be restored despite optimal medical therapy.

4. IV Nutrition (Total Parenteral Nutrition – TPN)

• Total parenteral nutrition (TPN) is reserved for very severe, refractory cases when both oral and enteral feeding fail. TPN carries significant risks (infection, thrombosis, liver dysfunction) and is not first-line nutritional support.

5. Considerations During Pregnancy

• Some medications carry risks during pregnancy, so it is crucial to consult a doctor before starting any treatment.

Early medical intervention and proper hydration are essential to managing severe nausea and vomiting effectively.

Consulting a healthcare provider as soon as possible is essential if symptoms of hyperemesis gravidarum are suspected or if there is a history of HG in previous pregnancies. Symptoms that warrant a doctor's consultation include persistent and severe nausea and vomiting that interfere with daily activities and nutrition, weight loss exceeding 5% of pre-pregnancy weight, dehydration indicated by excessive thirst or decreased urine output, electrolyte imbalances identified through blood tests, and psychological distress or significant impact on daily life due to symptoms. If you have a history of HG, discussing your previous experiences and developing a care plan with your healthcare provider before becoming pregnant is advisable. This plan should include pre-emptive treatments such as vitamin B6 supplements and first-line medications for morning sickness. Ensure that your healthcare provider understands your medical history and is prepared to support you with a cohesive hyperemesis gravidarum treatment plan. If symptoms of HG start during pregnancy, seek medical attention promptly, as early treatment can help manage symptoms and prevent complications such as malnutrition, dehydration, and electrolyte imbalances.

• HG affects approximately 0.3–3% of pregnancies, depending on diagnostic criteria.
• Symptoms of HG include persistent and severe nausea and vomiting, weight loss, dehydration, and electrolyte imbalances.
• While the exact cause of HG is unknown, it is believed to be related to hormonal changes during pregnancy.
• Treatment for HG may include dietary changes, medications, and, in severe cases, hospitalisation for intravenous fluids and nutrition.
• Although preventing HG with certainty is not currently possible, steps such as taking a multivitamin containing vitamin B6 before pregnancy and maintaining a healthy diet may help reduce the severity of symptoms.
• If symptoms of HG are suspected or there is a history of HG in previous pregnancies, it is essential to consult a healthcare provider promptly for proper diagnosis and treatment.