Morning sickness

Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. Typically the symptoms occur between the 4th and 16th week of pregnancy. About 10% of women still have symptoms after the 20th week of pregnancy. A severe form of the condition is known as hyperemesis gravidarum and results in weight loss.

The cause of morning sickness is unknown but may relate to changing levels of the hormone human chorionic gonadotropin. Some have proposed that morning sickness may be useful from an evolutionary point of view. Diagnosis should only occur after other possible causes have been ruled out. Abdominal pain, fever, or headaches are typically not present in morning sickness.

Taking prenatal vitamins before pregnancy may decrease the risk. Specific treatment other than a bland diet may not be required for mild cases. If treatment is used the combination of doxylamine and pyridoxine is recommended initially. There is limited evidence that ginger may be useful. For severe cases that have not improved with other measures methylprednisolone may be tried. Tube feeding may be required in women who are losing weight.

Morning sickness affects about 70–80% of all pregnant women to some extent. About 60% of women experience vomiting. Hyperemesis gravidarum occurs in about 1.6% of pregnancies. Morning sickness can negatively affect quality of life, result in decreased ability to work while pregnant, and result in health-care expenses. Generally, mild to moderate cases have no effect on the fetus, and most severe cases also have normal outcomes. Some women choose to have an abortion due to the severity of symptoms. Complications such as Wernicke encephalopathy or esophageal rupture may occur, but very rarely.