Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum
Nausea and vomiting of pregnancy (NVP), generally referred to as “morning sickness,” is a common pregnancy discomfort. Its association with pregnancy was documented on papyrus dating as far back as 2000 bce. The earliest reference is in Soranus’ Gynecology from the 2nd century ce.s9 Some degree of nausea, with or without vomiting, occurs in 50% to 90% of all pregnancies. It generally begins at about five to six weeks of gestation and usually abates by 16 to 18 weeks gestation. As many as 15% to 20% of pregnant women will continue to experience some degree of nausea and vomiting of pregnancy into the third trimester, and approximately 5% will continue to experience it until birth. The socioeconomic impact of nausea and vomiting of pregnancy on time lost from either paid employment or household work is substantial, with one study reporting as many as 8.6 million hours of paid employment and 5.8 million hours of household work lost each year because of nausea and vomiting of pregnancy. Additionally, women experiencing more extreme versions of nausea and vomiting of pregnancy or hyperemesis gravidarum are vulnerable to social isolation, and possibly depression, as a result of their symptoms — they are simply too ill to engage in their normal social activities, or they isolate themselves in order to avoid the embarrassment of being caught vomiting publicly.
Morning sickness is actually a misnomer for this condition, as the symptoms are not limited to the morning, and may occur at any time of day. In fact, in 80% of women, symptoms persist throughout the day. It has been jokingly said the condition is called morning sickness because it starts in the morning and lasts all day. Both the etiologies and role of nausea and vomiting of pregnancy in pregnancy remain uncertain. Several physiologic etiologies have been proposed. It has been suggested that nausea and vomiting of pregnancy actually serves a protective function for the pregnancy. Flaxman and Sherman propose, for example, that morning sickness causes women to avoid foods that might be dangerous to themselves or their embryos, especially foods that, prior to widespread refrigeration, were likely to be heavily laden with microorganisms and their toxins. Studies have demonstrated that women who experience some degree of nausea and vomiting of pregnancy are less likely to miscarry or experience stillbirth.’
Symptoms Of Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum
The spectrum of symptoms and severity of nausea and vomiting of pregnancy range from mild to severe nausea, gagging, and retching to vomiting, and from mild discomfort with minimal food and smell aversions to severe. Extreme nausea and vomiting of pregnancy with unrelenting vomiting is called hyperemesis gravidarum, and is a medical condition, as opposed to nausea and vomiting of pregnancy, which in its milder forms is actually considered normal.
Symptoms of hyperemesis gravidarum include persistent vomiting (and often dry heaving as well) accompanied by weight loss exceeding 5% of prepregnancy body weight and ketonuria unrelated to other causes. It is generally incapacitating. It is estimated that hyperemesis occurs in 0.3% to 2% of pregnancies. Hyperemesis typically persists into the second trimester, and may continue until the time of birth. Hospitalization for hyperemesis is common, peaking at approximately 9 weeks gestation and leveling off at around 20 weeks. The pathogenesis of hyperemesis is unknown. Symptoms generally resolve by midpregnancy regardless of treatment. When properly treated, hyperemesis gravidarum is associated with a very low morbidity and mortality rate. Without adequate treatment, the mother may experience micronutrient deficiency, Wernicke’s encephalopathy caused by vitamin Bx deficiency, and consequences of malnutrition, for example, propensity toward infection or slow healing wounds. There does not appear to be an increased risk of birth defects in babies born to mothers with hyperemesis gravidarum, and although women with hyperemesis gravidarum may experience substantial weight loss in early pregnancy, as long as overall pregnancy weight gain is normal, there does not appear to be any difference in birth weight in women with hyperemesis gravidarum. Low birth weight is likely to occur in babies born to mothers who do not make up their pregnancy weight later in pregnancy.
Risk Factors For Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum
In a study of the risk factors for nausea and vomiting of pregnancy and hyperemesis, hyperthyroid disorders, psychiatric illness, previous molar pregnancy, pre-existing diabetes, gastrointestinal disorders, and asthma were all statistically significant risks, whereas maternal smoking and maternal age older than 30 were associated with decreased risk. Singleton female pregnancies, as well as multiple pregnancies, were associated with statistically significant increased risk of hyperemesis. Women with gastroesophageal reflux disease (GERD) are more likely to experience nausea and vomiting of pregnancy and hyperemesis. During pregnancy, esophageal, gastric, and small bowel motility are impaired as a result of smooth muscle relaxation fostered by increased levels of female sex hormones. This dysmotility could contribute to nausea and vomiting of pregnancy. Hormonal changes leading to changes in lower esophageal tone may also lead nausea and vomiting of pregnancy, in addition to heartburn. Psychological factors, particularly feelings of ambivalence about the pregnancy, have been suggested as part of the etiology; however, this theory has not been borne out by psychological evaluation of women with this condition, and studies are confounded by the fact that the experience of hyperemesis can lead to feelings of ambivalence. Elevated serum concentrations of estrogen and progesterone have been implicated as pathogenic factors, as have decreased prolactin levels and elevated human chorionic gonadotropin (hCG); however, none of these associations has been definitely demonstrated. Other proposed pathogenic factors include abnormal gastric motility, nutrient deficiencies, alterations in lipid levels, changes in the autonomic nervous system, genetic factors, and infection with Helicobacter pylori.
There is no specific diagnosis for nausea and vomiting of pregnancy. Nausea, accompanied by a missed menstrual period, or other confirmation of pregnancy, is usually adequate. Hyperemesis gravidarum, likewise, is a clinical diagnosis. There is not a definitive point of demarcation separating a diagnosis of nausea and vomiting of pregnancy from hyperemesis. The sheer persistence of the vomiting accompanied, as mentioned, by weight loss exceeding 5% of prepregnancy body weight and ketonuria unrelated to other causes is considered diagnostic. Although nausea and vomiting of pregnancy can cause significant inconvenience and changes in daily activities, hyperemesis is usually markedly debilitating, and many practitioners consider persistent vomiting and marked debility diagnostic of hyperemesis. Women with persistent vomiting are evaluated by ultrasound for the presence of tropho-blastic disease (e.g., hydatidiform mole) and multiple pregnancy. Serum electrolyte levels, as well as FT4 are also checked. Differential diagnosis for nausea and vomiting is extensive; other pathologic causes ranging from endocrine disorders to neoplastic conditions should be ruled out, particularly for nausea and vomiting that commence after 10 weeks gestation. Concurrent signs such as abdominal pain, fever, headache, goiter, abnormal neurologic findings, diarrhea, constipation, or hypertension suggest a problem other than nausea and vomiting of pregnancy or hyperemesis gravidarum. Nausea and vomiting that occur in the latter half of pregnancy could be associated with preeclampsia, HELLP syndrome (hemolysis, elevated liver function tests, low platelets), and fatty liver of pregnancy, and should be ruled out.
Conventional Treatment Of Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum
Conventional treatment for both nausea and vomiting of pregnancy and hyperemesis gravidarum includes supportive therapy, nonpharmacologic, and pharmacologic interventions. Nausea that is mild and self-limiting is considered normal, and does not require treatment. The supportive and non-pharmacologic therapies used in conventional care are the same as those used in conjunction with botanical care, and are described under Nonpharmacologic Treatment of nausea and vomiting of pregnancy and Hyperemesis gravidarum. Pharmacologic treatment may be necessary in severe or refractory cases, and after nonpharmacologic interventions have failed to bring relief or improvement, in order for women to function in their daily lives and gain nutrition without IV or enteral feeding methods.
The mainstay of pharmacologic treatment for these conditions is the use of antiemetic drugs. Antiemetics have been shown to be more effective than placebo, and do not appear to increase birth defect risk; however, evidence of safety from well-designed trials is not substantial. Thus, many women and doctors remain wary of their use, especially in the first trimester. Most women are content to wait out the normal, mild to moderate first trimester nausea without significant intervention as long as it does not interfere with their ability to function.
When pharmacologic intervention is required, it is advisable to start with drugs with minimal known side effects, and progress to other drugs only if these are ineffective and antiemetic therapy is necessary. Antihistamines are also successfully used as antiemetics to control nausea and vomiting of pregnancy. A meta-analysis reviewed 24 controlled studies including over 200,000 first trimester exposures and found that these medications had a protective effect, with a reduction in birth defects. A number of other antiemetic medications are used including several of the dopamine antagonists, appear to be helpful and are not associated with teratogenicity.
Corticosteroids have been used for women with severe, unresponsive hyperemesis. The mechanisms of action are poorly understood, and the results of controlled trials have been contradictory. Prolonged use of oral corticosteroids in pregnancy may increase the risk of preterm premature rupture of membranes (PPROM), as well as the risk of cleft palate, the latter when administered prior to 10 weeks of gestation. Given the potential risks and undetermined benefits, ACOG advises against the use of corticosteroids for treatment of hyperemesis unless as a last resort.
See nonpharmacologic treatments.
Treatment Summary For Nausea And Vomiting Of Pregnancy And Hyperemesis Gravidarum
The following treatments may be tried individually or in combination, according to the woman’s needs, preferences, and severity of her condition.
Nonpharmacologic / Nutritional Treatments
• Avoid triggers
• Avoid hypoglycemia with small, frequent intake of foods and beverages
• High protein, low fat snacks
• Dry crackers, pretzels, pasta, baked potatoes, or other bland, slightly salty foods
• Carbonated beverages; beverages with lemon or lime; ginger ale, slightly salty clear broth or bouillon
• Supplementation with vitamin B6 (10 or 25 mg three times per day) significantly reduced the severity of morning sickness.
• Acupuncture / acupressure at P6, or an individually designed professional acupuncture program
• Hypnosis or psychotherapy
• Nutritive enemas or parenteral nutrition in severe cases
There are NO drugs that are FDA-approved for the treatment of morning sickness. However, drugs such as dimenhydrinate, diphenhydramine, and melamine have been used. Prescription medications used include prochlorperazine (Compazine®), ondansetron (Zofran®), meclizine (Antivert®), promethazine (Phenergan®), and metoclopramide (Reglan®).
• Hospitalization when there is complete inability to eat or drink, or if there is persistent weight loss
• Ginger root has demonstrated efficacy and safety, up to 1 g / day, for the treatment of nausea and vomiting of pregnancy and hyperemesis
• Other herbs include peppermint, wild yam, dandelion root, chamomile, and black horehound. These have a traditional basis of safe and effective use and can be taken regularly throughout the day.
• Peppermint oil can be used as aromatherapy as needed.
• Marijuana is commonly used as self-medication for nausea, vomiting, and loss of appetite. Results of safety studies in pregnancy are contradictory and the legal status makes use controversial; nonetheless, practitioners should inquire about patient’s use and advise safe use if the patient is likely to continue to use regardless of practitioner’s recommendations (i.e., avoid potentially adulterated “street” products).