According to published research, about 50% of women have nausea and vomiting in early pregnancy, and an additional 25% have nausea alone. The term “morning sickness” is a misnomer because it often persists throughout the day. In about 35% of women who have morning sickness, nausea and vomiting are clinically significant. As a result, family relationships may be negatively impacted or time may be lost at work. “Morning sickness symptoms may lead to dehydration and weight loss that require hospitalization in some cases,” says Jennifer R. Niebyl, MD, who described evidence-based strategies for managing nausea and vomiting in pregnant women in a review published in the October 14, 2010 New England Journal of Medicine.
“Nausea and vomiting in pregnancy can severely reduce quality of life for women, but progress has been made in the means to treat it,” says Dr. Niebyl. “Pregnant women with dehydration are recommended to receive IV fluid replacement with multivitamins, especially thiamine. If the vomiting continues after 12 hours of IV therapy, hospitalization may be required.” Enteral or parenteral nutrition may also benefit patients, but should be reserved for those who continue to experience weight loss despite pharmacologic therapies.
Examining the Clinical Course
The cause of nausea and vomiting in pregnancy is unclear, and there are no evidence-based means to identify women who are risk for this complication. What is known, however, is that the onset of the nausea is typically within 4 weeks after the last menstrual period in most patients. The problem typically peaks at about 9 weeks gestation. “Research shows that about 60% of cases resolve by the end of the first trimester, and 91% resolve by 20 weeks gestation,” says Dr. Niebyl. “Nausea and vomiting are less common in older women, multiparous women, and smokers.”
The clinical course of nausea and vomiting during pregnancy correlates closely with the level of human chorionic gonadotropin (hCG) (Figure 1). Experts believe that hCG stimulates estrogen production from the ovary, a process that may increase the likelihood of nausea and vomiting. Women with higher hCG levels are at higher risk for these symptoms than other pregnant women. Vitamin B deficiency may also contribute to the problem. Use of multivitamins containing vitamin B has been shown to reduce the incidence of nausea and vomiting.
Reviewing Patient Management
Women should be advised to take various precautions to minimize their risk for nausea and vomiting. “Women should avoid exposure to odors, foods, or supplements that may trigger nausea,” Dr. Niebyl says. “Fatty or spicy foods and iron tablets can sometimes trigger nausea. Eating small amounts of food several times a day and drinking fluids between meals may be helpful. Eating foods that are bland, dry, and high in protein can also be of benefit. Interestingly, women are often advised to manage nausea by keeping crackers handy in the morning and avoiding an empty stomach. However, published data on this are lacking.” Women who have persistent nausea and vomiting and high concentrations of ketones require IV hydration with multivitamins and follow-up measurements of urinary ketones and electrolyte levels. Antiemetic agents should be prescribed in these patients (Figure 2).
About 10% of women with nausea and vomiting in pregnancy will need medication. Pharmacologic therapies include vitamin B6, antihistamines, prokinetic agents, and other drugs. “Over-the-counter (OTC) medications have been studied extensively and appear to be effective,” says Dr. Niebyl. “The OTC combination of vitamin B6 and doxylamine was removed from the market in 1983 because of allegations of teratogenicity, but these allegations were later found to be unjustified. More recently, however, this combination has been associated with a 70% reduction in nausea and vomiting. As a result, the American College of Obstetricians and Gynecologists now recommend it as first-line therapy. Physicians shouldn’t be concerned about the risks of this treatment.” Prokinetic agents, 5-hydroxytryptamine3-receptor antagonists, and other drugs may also be effective for nausea and vomiting in some patient groups, but more research is needed to explore appropriate patient selection with these treatment options.
Consider Alternative & Complementary Therapies
Alternative therapies, such as acupuncture and ginger, have also been studied for nausea and vomiting in pregnancy. “The data on acupuncture are unclear as of now, so it’s not currently recommended,” says Dr. Niebyl. “Ginger, on the other hand, is available OTC and has demonstrated efficacy similar to that of vitamin B6. Its most common adverse effects (reflux and heartburn) aren’t serious. That said, ginger is considered a food supplement rather than a drug and isn’t regulated by the FDA and may not be available in hospital pharmacies. Fortunately, healthcare providers have many options to choose from to combat nausea and vomiting in pregnancy. The hope is more data will emerge in the future and further improve how patients are managed.”
Niebyl JR. Nausea and vomiting in pregnancy. N Engl J Med. 2010; 363:1544-1550. Available at:http://www.nejm.org/doi/full/10.1056/NEJMcp1003896.
Attard CL, Kohli MA, Coleman S, et al. The burden of illness of severe nausea and vomiting of pregnancy in the United States. Am J Obstet Gynecol. 2002;186:Suppl:S220-S227.
Mazzotta P, Stewart D, Atanackovic G, Koren G, Magee LA. Psychosocial morbidity among women with nausea and vomiting of pregnancy: prevalence and association with anti-emetic therapy. J Psychosom Obstet Gynaecol. 2000;21:129-136.
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