O20-O29: Other maternal disorders predominantly related to pregnancy

O21: Excessive vomiting in pregnancy

Excessive vomiting in pregnancy, known as hyperemesis gravidarum under ICD-10 group range O21, is a condition that affects some pregnant women. It is characterized by severe and persistent nausea and vomiting, which is usually more extreme than the typical morning sickness experienced in early pregnancy. The exact cause remains unknown, but it's thought to be related to hormonal changes that occur during pregnancy. Despite being labeled 'excessive', the amount of vomiting can vary greatly, and there's no standard definition for how much is too much. This condition can lead to dehydration, weight loss, and electrolyte imbalances if untreated. Unlike typical morning sickness, symptoms can persist beyond the first trimester and can interfere with a woman's daily activities. It can affect all systems in the body due to the potential for severe dehydration and malnutrition. The good news is that while hyperemesis gravidarum can be quite uncomfortable, with appropriate medical care, it usually doesn't pose a risk to the baby.