Hyperemesis gravidarum

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Hyperemesis gravidarum (HG) is a pregnancy complication characterized by severe nausea, vomiting, weight loss, and possibly dehydration. Feeling faint may also occur. It is considered a more severe form of morning sickness. Symptoms often get better after the 20th week of pregnancy but may last the entire pregnancy duration. 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, and sometimes even after. A small percentage rarely vomit, but the nausea still causes most of the same issues that hyperemesis with vomiting does.

Key facts

The exact causes of hyperemesis gravidarum are unknown. Risk factors include the first pregnancy, multiple pregnancy, obesity, prior or family history of HG, and trophoblastic disorder. 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. A December 2023 study indicated a link between HG and abnormally high levels of the hormone GDF15, as well as increased sensitivity to that specific hormone.

When to seek professional help

Professional care is associated with severe symptoms. Diagnosis is usually made based on observed signs and symptoms, and HG has been technically defined as more than three episodes of vomiting per day such that weight loss of 5% or three kilograms has occurred and ketones are present in the urine. Other potential causes of the symptoms should be excluded, including urinary tract infection and an overactive thyroid. Hospitalization may be required due to the severe symptoms associated. 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.

Source: Hyperemesis gravidarum (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-10-03.