It’s common for pregnant women to experience some degree of nausea and vomiting — about 90% of them do. But 0.5% to 2% of women experience an extreme form of nausea and vomiting in pregnancy, a condition known as hyperemesis gravidarum (HG). It results in dehydration, loss of important electrolytes, malnutrition and weight loss, and is life-threatening if left untreated.

Since its prevalence worldwide is low, very little is known about HG, making it difficult for women to understand and navigate the condition.

What is hyperemesis gravidarum?

HG is a kind of morning sickness experienced by pregnant women that is characterized by severe and persistent nausea and vomiting. The difference between HG and common morning sickness is that while in the latter, nausea is accompanied by vomiting occasionally, for women suffering from HG, the nausea is accompanied by severe vomiting (three to four times a day), according to the American Pregnancy Association (APA). While nausea associated with normal morning sickness, subsides within 12 weeks, with HG, nausea doesn’t subside and may continue throughout the pregnancy.

When does HG develop?

According to the APA, women may start experiencing symptoms of HG between four and six weeks of pregnancy, and these symptoms may peak between nine and 13 weeks. Although some women may experience relief between the 14th and the 20th week, 20% of women may end up needing care for HG throughout their pregnancy.

What are the signs or symptoms of HG?

Besides experiencing severe nausea and vomiting, those suffering from HG might become averse to food. They might notice a decrease in urination, experience headaches, extreme fatigue and some episodes of fainting. There might be some signs of anxiety and/or depression too, according to Healthline.

What does having HG mean for the mother and the baby?

HG can be severe enough to result in weight loss of more than 10 pounds (4.5 kg), states clevelandclinic.org. With frequent vomiting, women may also end up suffering from dehydration and loss of vitamins and minerals. In most cases, it leads to hospitalization so medical professionals can help restore lost fluids and nutrients. Because symptoms subside and recur, HG could also result in frequent hospitalizations. A study states infants born to women suffering from HG are more likely to have low birth weight, or be small for their gestational age, and be born prematurely. Researchers have also observed low birth weight to be more common in babies of women who were hospitalized frequently as compared to those who were hospitalized only once.

What causes HG?

The exact cause of hyperemesis gravidarum is not known. Most researchers studying the condition attribute it to hormonal fluctuation because both morning sickness and HG seem to have a connection with human chorionic gonadotropin — the hormone produced by the placenta during pregnancy. The body produces large amounts at a rapid rate early in pregnancy and if the hormone’s levels continue to rise throughout, then it can cause severe nausea and vomiting resulting in HG. But no studies have confirmed this yet.

Related on The Swaddle:

Pregnancy Diet 101: Weight Gain and Morning Sickness

However, some theories about what causes HG include vitamin B deficiency, hyperthyroidism, gastroesophageal reflux. In some cases, HG can also be caused due to helicobacter pylori or a bacterial infection that causes stomach inflammation, peptic ulcer disease and certain types of stomach cancer.

Who is at risk for HG?

According to Healthline, women with a history of HG in the family, or those carrying more than one baby, are at a high risk of experiencing HG. Being overweight or a first-time mother also pose as risks for suffering from HG. Women suffering from trophoblastic disease that occurs when there’s an abnormal growth of cells inside the uterus can also be at risk of suffering from HG.

How does HG get diagnosed?

A thorough clinical evaluation, detailed patient history and the identification of symptoms common with HG, such as persistent vomiting and nausea, can help with the diagnosis of HG.

Is HG treatable?

The most immediate form of treatment is hospitalization, during which intravenous (IV) therapy will help restore lost fluids and replace electrolytes. Cleveland Clinic suggests food should be avoided until vomiting stops and dehydration has been addressed. In some cases, doctors may prescribe food via enteral feeding or through the intestines or by injection via another route, also known as parenteral feeding. At other times, doctors may also administer vitamin supplements, especially B6, C and thiamine (vitamin B1) to make up for the lost nutrients.

After this line of treatment, doctors may reintroduce fluids and meals high in carbohydrates and low in fat gradually into patients’ diets.

At times, women may need counseling to cope with the complications caused by HG.

Managing HG at home may depend on the severity of the symptoms. Smaller and more frequent meals, dry foods, and plenty of fluids can help manage symptoms of HG. Depending on the frequency and intensity of symptoms, the APA advises it’s best to approach a doctor.