Nausea and vomiting in pregnancy

Last reviewed: March 2020

Last updated: February 2020

12 Feb 2020

EMA's safety committee recommends restricting the use of ondansetron during the first trimester of pregnancy

The European Medicines Agency's (EMA's) pharmacovigilance risk assessment committee (PRAC) has recommended limiting the use of ondansetron during the first trimester of pregnancy.[19]

The PRAC review concluded that women who used ondansetron during the first trimester of pregnancy had an increased risk of birth defects, specifically cleft lip and/or palate. In one study, there were an additional 3 cases of orofacial cleft per 10,000 pregnancies exposed to ondansetron.[20] The available data on the risk of cardiac defects with ondansetron use show conflicting results.[20][21] However, the UK Teratology Information Service (UKTIS), in collaboration with the European Network of Teratology Information Services (ENTIS), issued a joint statement in response to the recommendations from the EMA PRAC regarding the use of ondansetron in the first trimester of pregnancy. UKTIS and ENTIS suggest ondansetron should still be considered an option for patients with severe vomiting in pregnancy in whom first-line treatments have failed, noting in their statement that there is much more information available about safety during pregnancy for ondansetron than for other antiemetic drugs, with data now available from over 168,000 women treated during the first trimester.[22] The UK Medicines and Healthcare products Regulatory Agency (MHRA) also issued a drug safety update for ondansetron that provides similar advice.[23]

This recommendation is in line with the current Royal College of Obstetricians and Gynaecologists (RCOG) recommendations that ondansetron should be reserved as a second-line agent for the treatment of nausea and vomiting in pregnancy, including hyperemesis gravidarum.[24] The drug should only be used during pregnancy if the benefits of treatment are considered to outweigh any potential fetal risks, and women must receive adequate counseling about both benefits and risks of treatment.

See Management: approach

See Management: treatment algorithm

Original source of updateexternal link opens in a new window

Summary

Affects approximately 75% of pregnant women.

Typically begins between the fourth and seventh week after the last menstrual period and resolves in the second trimester.

Etiology remains unclear. There is some evidence that it is related to hormone levels of human chorionic gonadotropin and estrogen.

Hyperemesis gravidarum represents the most severe form of nausea and vomiting of pregnancy. While there is lack of consensus of definition, most agree that clinical features include persistent vomiting, volume depletion, ketosis, electrolyte disturbances, and weight loss.

Initial therapy should be conservative. This may include nonpharmacologic treatments such as diet modification, emotional support, ginger, and acupressure.

Severe cases may require hospitalization, intravenous fluids, antiemetics, corticosteroids, and total parenteral nutrition.

Definition

Nausea and vomiting in pregnancy (NVP), commonly referred to as morning sickness, typically begins between the fourth and seventh week after the last menstrual period. It is characterized by nausea and vomiting that occur more frequently during the morning hours, and typically resolves in the second trimester. Hyperemesis gravidarum is the most severe form of NVP and is characterized by persistent vomiting, volume depletion, ketosis, electrolyte disturbances, and weight loss.