Hyperemesis gravidarum

The exact causes of hyperemesis gravidarum are unknown. Diagnosis is usually made based on the observed signs and symptoms. Other potential causes of the symptoms should be excluded, including urinary tract infection, and an overactive thyroid. Treatment includes drinking fluids and a bland diet. Some people require intravenous fluids. HG is estimated to affect 0.3–2.0% of pregnant women, although some sources say the figure can be as high as 3%. While previously known as a common cause of death in pregnancy, with proper treatment this is now very rare. Those affected have a lower risk of miscarriage but a higher risk of premature birth. Some pregnant women choose to have an abortion due to HG symptoms. Loss of 5% or more of pre pregnancy body weight
Dehydration, causing ketosis,
Physical and emotional stress
Difficulty with activities of daily living

Symptoms can be aggravated by hunger, fatigue, prenatal vitamins (especially those containing iron), and diet. Many women with HG are extremely sensitive to odors in their environment; certain smells may exacerbate symptoms. Excessive salivation, also known as sialorrhea gravidarum, is another symptom experienced by some women. Hyperemesis gravidarum tends to occur in the first trimester of pregnancy and lasts significantly longer than morning sickness. While most women will experience near complete relief of morning sickness symptoms near the beginning of their second trimester, some people with HG will experience severe symptoms until they give birth to their baby, and sometimes even after giving birth. A small percentage rarely vomit, but the nausea still causes most (if not all) of the same issues that hyperemesis with vomiting does.

The effects of HG on the fetus are mainly due to electrolyte imbalances caused by HG in the mother. Women with severe hyperemesis who gain less than during pregnancy tend have newborns with lower birth weight or are smaller for gestational age. They also tend to give birth before 37 weeks gestation. There is no significant difference in the neonatal death rate in infants born to mothers with HG compared to infants born to mothers who do not have HG.

Though the exact cause of HG is unknown, there are numerous theories. It is thought that HG is caused by a combination of factors, many of which may vary between women, some of which include a genetic predisposition. One factor is an adverse reaction to the hormonal changes of pregnancy, in particular, elevated levels of beta human chorionic gonadotropin (β hCG). This theory would also explain why hyperemesis gravidarum is most frequently encountered in the first trimester (often around 8–12 weeks of gestation), as β hCG levels are highest at that time and decline afterward. Another postulated cause of HG is an increase in maternal levels of estrogens (decreasing intestinal motility and gastric emptying leading to nausea/vomiting). In a 2023 study, Fejzo further linked GDF15 as cause when present in high levels due to fetal cell production in contrast with the natural low levels which result maternal sensitivity.

Hyperemesis gravidarum is considered a diagnosis of exclusion. Criteria for diagnosing HG in a patient generally includes vomiting that results in significant dehydration and weight loss (at least 5% of the patients pre pregnancy weight). Urinalysis is usually preformed and blood samples may be taken to check for ketonuria, electrolyte imbalances, and complete blood counts, all of which could indicate HG or prompt an alternative diagnosis. Women experiencing hyperemesis gravidarum often are dehydrated and lose weight despite efforts to eat. Similar to the onset of standard bouts of morning sickness, the nausea and vomiting with hyperemesis typically starts between 5 and 6 weeks into pregnancy.

Dry, bland food and oral rehydration are first line treatments. Due to the potential for severe dehydration and other complications, HG is treated as an emergency. If conservative dietary measures fail, more extensive treatment such as the use of antiemetic medications and intravenous rehydration may be required. If oral nutrition is insufficient, intravenous nutritional support may be needed. A and B vitamins are depleted within two weeks, so extended malnutrition indicates a need for evaluation and supplementation. In addition, electrolyte levels should be monitored and supplemented; of particular concern are sodium and potassium. After IV rehydration is completed, patients typically begin to tolerate frequent small liquid or bland meals. After rehydration, treatment focuses on managing symptoms to allow normal intake of food. However, cycles of hydration and dehydration can occur, making continuing care necessary. Home care is available in the form of a peripherally inserted central catheter (PICC) line for hydration and nutrition. Home treatment is often less expensive and reduces the risk for a hospital acquired infection compared with long term or repeated hospitalizations.

A number of antiemetics are effective and safe in pregnancy including: pyridoxine/doxylamine, antihistamines (such as diphenhydramine), and phenothiazines (such as promethazine). With respect to effectiveness, it is unknown if one is superior to another for relieving nausea or vomiting. some have questioned its effectiveness in HG. Ondansetron may be beneficial, however, there are some concerns regarding an association with cleft palate, and there is little high quality data. However, hydrocortisone and prednisolone are inactivated in the placenta and may be used in the treatment of hyperemesis gravidarum after 12 weeks.

Women not responding to IV rehydration and medication may require nutritional support. Patients might receive parenteral nutrition (intravenous feeding via a PICC line) or enteral nutrition (via a nasogastric tube or a nasojejunal tube). There is only limited evidence from trials to support the use of vitamin B6 to improve outcome. The use of ginger products may be helpful, but evidence of effectiveness is limited and inconsistent, though three recent studies support ginger over placebo. However, the incidence of HG is only 0.3–1.5%.

Hyperemesis gravidarum is from the Greek hyper , meaning excessive, and emesis, meaning vomiting, and the Latin gravidarum, the feminine genitive plural form of an adjective, here used as a noun, meaning "pregnant [woman]". Therefore, hyperemesis gravidarum means "excessive vomiting of pregnant women".

Author Charlotte Brontë is often thought to have had hyperemesis gravidarum. She died in 1855 while four months pregnant, having been affected by intractable nausea and vomiting throughout her pregnancy, and was unable to tolerate food or even water. Catherine, Princess of Wales was hospitalised due to hyperemesis gravidarum during her first pregnancy, and was treated for a similar condition during the subsequent two. Comedienne Amy Schumer cancelled the remainder of a tour due to hyperemesis gravidarum.

In previous centuries, the cause was unknown, and various false claims were made, such as the severe vomiting being caused by the woman's rejection of femininity, a manifestation of a subconscious desire to terminate the pregnancy, or being an attention seeking behavior. These erroneous beliefs led to various abusive practices, such as isolating them from their friends and family, or leaving severely ill women to lie in the vomit when they were too weak to clean themselves, which have since been condemned by healthcare professionals and medical organizations such as the College of French Gynecologists and Obstetricians. The HER Foundation is grassroots network of HG survivors and experts. Hyperemesis gravidarum is estimated to cost US$3 billion per year for hospitalization costs alone, not including the direct medical costs of additional outpatient medical appointments, prescription drugs, and home health care, or any indirect costs such as lost work. In the 15 years between 2007 and 2023, the US National Institutes of Health approved six research grants to study hyperemesis gravidarum, with a total of US$2.1 million dollars in research funding for all six grants combined (an average of $350,000 per grant or $140,000 per year).