Hyperemesis

Severe vomiting associated with early pregnancy

  • Stress may aggravate the condition
  • Age and genetics are not significant factors

Hyperemesis is vomiting that occurs in early pregnancy and is so extreme that no food or fluids can be kept down. The condition is more severe than common morning sickness (see Common complaints of normal pregnancy). In morning sickness, nausea and vomiting also occur during early pregnancy, as a result of hormonal changes taking place in the body, but are usually not serious and can often be relieved by taking a few simple measures.

When morning sickness occurs in pregnancy, the mother continues to gain weight steadily as the pregnancy progresses. In contrast, a mother who has hyperemesis will lose weight. The excessive vomiting eventually leads to dehydration, which, in turn, decreases urine volume and causes an imbalance of chemicals in the blood. If hyperemesis is allowed to continue without treatment, dehydration may become life-threatening for both the mother and the fetus.

The cause of hyperemesis is usually not known, although it is thought that very high amounts of human chorionic gonadotropin (HCG), a hormone that is produced by the placenta in pregnancy, may contribute to excessive nausea and vomiting in the mother. High levels of HCG occur if more than one fetus is present (see Multiple pregnancy and its problems). Less commonly, very high amounts of HCG are produced if a tumour develops from part of the placenta (see Molar pregnancy). Occasionally, a urinary tract infection may possibly cause vomiting in pregnancy accompanied by fever and pains in the sides. Psychological factors, such as emotional stress, may aggravate hyperemesis in some women.

What might be done?

If you are unable to keep any food or fluids down, you will need to be admitted to hospital for treatment. You may need to have blood tests so that the doctors can assess the degree of dehydration that has occurred as a result of severe vomiting, and a urine test in order to check for a urinary tract infection. You may also undergo ultrasound scanning (see Ultrasound scanning in pregnancy) to investigate the possibility of a multiple or molar pregnancy.

Usually, dehydration is treated in hospital with intravenous fluids. You may also be given drugs that help to stop the vomiting (see Antiemetic drugs). If the urine tests have confirmed the presence of a urinary tract infection, antibiotics will probably be given to treat it.

Once the vomiting has been treated, and you can begin to keep down food and fluids, you should be able to start eating small quantities of plain food and gradually build up to a normal diet. However, the vomiting often recurs, and further stays in hospital may be necessary so that adequate measures may be taken to prevent dehydration. Hyperemesis usually subsides after the 14th week of pregnancy, although the condition is likely to recur in subsequent pregnancies.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

Back to top