New Guidelines on Nausea, Vomiting in Pregnancy

Troy Brown, RN

December 22, 2017

The American College of Obstetricians and Gynecologists urges clinicians to treat nausea and vomiting of pregnancy as early as possible to prevent it from progressing to hyperemesis gravidarum, according to an updated practice bulletin.

The authors also explain that timing of symptom onset is important: "The timing of the onset of nausea and vomiting is important — symptoms of nausea and vomiting of pregnancy manifest before 9 weeks of gestation in virtually all affected women. When a patient experiences nausea and vomiting for the first time after 9 weeks of gestation, other conditions should be carefully considered in the differential diagnosis. A history of a chronic condition associated with nausea and vomiting that predates pregnancy should be sought (eg, cholelithiasis or diabetic gastroparesis)," they explain.

The American College of Obstetricians and Gynecologists's Committee on Practice Bulletins–Obstetrics, in collaboration with Susan M. Ramin, MD, associate director of the American Board of Obstetrics & Gynecology, Dallas, Texas, who is also from Baylor St. Luke's Medical Center and St. Luke's The Woodlands Hospital, both in Houston, Texas, published the practice bulletin online December 21 and in the January issue of Obstetrics & Gynecology. It replaces an earlier one published in September 2015.

Nausea affects approximately 50% to 80% of women during pregnancy, and approximately half of all pregnant women experience retching. At the more severe end of that spectrum is hyperemesis gravidarum, which can be debilitating and deplete a woman's nutrition.

"Hyperemesis gravidarum is the most common indication for admission to the hospital during the first part of pregnancy and is second only to preterm labor as the most common reason for hospitalization during pregnancy," the authors write.

"No single accepted definition of hyperemesis gravidarum exists. It is a clinical diagnosis of exclusion based on a typical presentation in the absence of other diseases that could explain the findings. The most commonly cited criteria include persistent vomiting not related to other causes, a measure of acute starvation (usually large ketonuria), and some discrete measure of weight loss, most often at least 5% of prepregnancy weight. Electrolyte, thyroid, and liver abnormalities also may be present," the authors explain.

Level A recommendations, which are made on the basis of good and consistent scientific evidence, include:

  • Use Vitamin B6 (pyridoxine) alone or in combination with doxylamine as first-line pharmacotherapy, as they are safe and effective.

  • Clinicians should encourage women to take prenatal vitamins for 1 month before fertilization, as it may decrease the incidence and severity of nausea and vomiting during pregnancy.

  • The American College of Obstetricians and Gynecologists recommends supportive therapy for abnormal maternal thyroid tests caused by gestational transient thyrotoxicosis or hyperemesis gravidarum, or both, and recommends against antithyroid medications.

Level B recommendations, which are made on the basis of limited or inconsistent scientific evidence, include:

  • Ginger may be used as a nonpharmacologic option, as it has had some beneficial effects in the treatment of nausea and vomiting of pregnancy.

  • Methylprednisolone has been effective in some refractory cases of severe nausea and vomiting of pregnancy; however, it should be considered a last-resort treatment as a result of its risk profile.

Level C recommendations, which are made primarily on the basis of consensus and expert opinion, include:

  • Early treatment of nausea and vomiting of pregnancy may help prevent it from progressing to hyperemesis gravidarum.

  • Intravenous hydration should be administered to patients who are unable to tolerate oral fluids for a prolonged period and if clinical signs of dehydration develop.

  • Strongly consider correction of ketosis and vitamin deficiency. Include dextrose and vitamins in therapy in cases of prolonged vomiting; consider administering thiamine before dextrose infusion to prevent Wernicke encephalopathy.

  • Begin enteral tube feeding (nasogastric or nasoduodenal) as first-line treatment to support nutrition for women with hyperemesis gravidarum who do not respond to medical therapy and who are unable to maintain their weight.

  • Use peripherally inserted central catheters only as a last resort in women with hyperemesis gravidarum, as significant complications are associated with this intervention, and there is the potential for severe maternal morbidity.

"After the patient has been hospitalized and a workup for other causes of severe vomiting has been undertaken, intravenous hydration, nutritional support, and modification of antiemetic therapy often can be accomplished at home," the authors explain. "Nevertheless, the option of hospitalization for observation and further assessment should be preserved for patients who experience a change in vital signs or a change in mental status, continue to lose weight, and are refractory to treatment," the authors conclude.

The authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2108;131:e15-e30. Abstract

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