Diseases and Conditions
Morning sickness
Overview
Symptoms
Causes
Risk factors
Complications
Prevention
Diagnosis
Treatment
Lifestyle and home remedies
Alternative medicine
Preparing for an appointment
Causes
The exact cause of morning sickness is unknown. Hormonal changes are thought to play a role in morning sickness. Rarely, severe or persistent nausea or vomiting may be caused by a medical condition unrelated to pregnancy — such as thyroid or liver disease.
