Nausea and Vomiting of Pregnancy
From Morning Sickness to Life-Threatening Hyperemesis Gravidarum
Jul 29, 2009
Approximately 80% of pregnant women suffer from nausea and vomiting of pregnancy, commonly known as “morning sickness.” Symptoms typically begin between the 4th and 7th week after the last menstrual period and resolve spontaneously by the 20th week of gestation.
However, a small percentage of pregnant women (10%) experience a more severe course, with the worst manifestation being hyperemesis gravidarum. Hyperemesis gravidarum is distinguished from morning sickness by weight loss (>5% of body weight) and the development of dehydration and ketoacidosis (the formation of ketones in the bloodstream, as measured by urinary ketones).
Pregnant women who experience persistent or worsening symptoms, or who lose weight in spite of conservative measures, should be evaluated medically. Once other causes of vomiting have been ruled out, treatment for hyperemesis should be individualized.
Causes of Nausea and Vomiting of Pregnancy
Through the years, many causes for morning sickness have been proposed; some are grounded in popular notion, and some are backed by clinical evidence:
- Psychological (e.g., hysteria or dependent personality): Few data support this theory, even though many physicians have been taught that psychological factors play a significant role. (Fairweather D. Nausea and vomiting in pregnancy. Am J Obstet Gynecol 1968;102:135-75)
- Changes in gastric motility: Some studies show that changing hormone levels adversely affect gastrointestinal activity. (Walsh J, et al. Progesterone and estrogen are potential mediators of gastric slow-wave dysrhythmias in nausea of pregnancy. Am J Physiol 1996;270(3 pt 1):G506-14; Broussard C, Richter J. Nausea and vomiting of pregnancy. Gastroenterol Clin North Am 1998; 27:123-51)
- Helicobacter pylori infection: One study showed that over 60% of women with hyperemesis gravidarum tested positive for the presence of H. pylori, while only 28% of women who did not have hyperemesis were infected. (Hayakawa S, et al. Frequent presence of Helicobacter pylorigenome in the saliva of patients with hyperemesis gravidarum. Am J Perinatol 2000;17:243-7)
- Hormones: The Merck Manual (18th Edition, 2006 pg 2196) cites rapidly increasing levels of hormones (estrogens and beta-HCG) as the basis for nausea and vomiting of pregnancy. However, earlier studies investigating hormonal changes as causes for hyperemesis have shown conflicting results. (Masson G, et al. Serum chorionic gonadotrophin (hCG), schwangerschaftsprotein 1 (SP1), progesterone and oestradiol levels in patients with nausea and vomiting in early pregnancy. Br J Obstet Gynaecol 1985;92:211-5; Soules M, et al. Nausea and vomiting of pregnancy: role of human chorionic gonadotropin and 17-hydroxyprogesterone. Obstet Gynecol 1980;55:696-700)
Risk Factors for Severe Nausea and Vomiting During Pregnancy
Conditions and factors associated with higher risk include:
- Multiple gestation (i.e., twins, etc.)
- Gestational trophoblastic disease (e.g., “molar” pregnancy)
- Trisomy 21 (Down syndrome) in the fetus
- Hydrops fetalis (fetal edema)
- Homemaker status (as opposed to “white-collar” or professional women)
- Age over 35 with a history of infertility
(From Quinlan J, Hill D. Nausea and vomiting of pregnancy. Am Fam Phys 2003;68(1):121-8)
Treatment for Nausea and Vomiting of Pregnancy
Once other conditions have been ruled out (e.g., appendicitis, pancreatitis, hepatitis, gallbladder disease, etc.), treatment is directed at replacing fluids and relieving symptoms.
Non-pharmacologic therapies include:
- Dietary modifications: frequent small meals; avoidance of smells and textures that trigger nausea; bland foods that are high in carbohydrates and low in fat; meals (especially salty foods) are often better tolerated in the morning; tart or sour liquids may be better tolerated than plain water.
- Emotional support: friends and family members should understand that mealtimes and schedules will be altered, and that mood changes may occur; medical advice should be sought for women who become depressed, who may be at risk for domestic abuse, or if substance abuse becomes an issue.
- Hypnosis: Medical hypnosis is an effective treatment for women with pregnancy-related vomiting, including hyperemesis gravidarum. (Fuchs K, et al. Treatment of hyperemesis gravidarum by hypnosis. Int J Clin Exp Hypn 1980;28:313-23)
- Accupressure: Application of pressure to the Neiguan point, three fingerbreadths above the wrist on the palmar surface, may help to control pregnancy-related nausea. Several commercial products—designed to alleviate motion sickness—apply pressure to this point.
- Ginger: This herbal remedy has been used successfully for pregnancy- and chemotherapy-related nausea. There are no published reports of fetal harm associated with ginger use during pregnancy. Ginger can be taken in teas, ginger ale, capsules, preserves and jams, or as tinctures (either glycerin or warmed alcohol extracts).
Pharmacologic Therapies
- Medical treatment includes vitamin B6, antiemetics such as Compazine, Tigan, or Phenergan, antihistamines like Benadryl or Dramamine, and anti-motility agents such as Reglan.
- For severe cases, hospitalization, intravenous fluid administration, corticosteroid therapy, and IV or tube feeding may be necessary. If a woman’s condition worsens in spite of intensive therapy, termination of the pregnancy must be considered.
Nausea and vomiting of pregnancy, though occasionally severe or even life-threatening, is usually just an unpleasant but self-limiting phase. With support and conservative management, 90% of affected women improve and deliver healthy infants.
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