The management of nausea and vomiting during pregnancy

Gestational malnutrition, hyperemesis gravidarum, and Wernicke's encephalopathy: What is missing?

Hyperemesis gravidarum (HG), or the severe nausea and vomiting of pregnancy, is one of the most dreaded complications of gestation, affecting between 1.5% and 3.0% of pregnant women. From the late 1800s to the mid-1980s, the etiology was frequently cited to have psychological and/or-later-perhaps hormonal origins, which have numbered at least 10. Current research has unearthed a genetic basis for HG that implicates growth differentiation factor 15, insulin-like growth factor binding protein 7, and hormone receptors (namely, glial cell line-derived neurogenic factor family receptor alpha-like and the progesterone receptor). Whatever the origins of this disease, it has caused immeasurable physiological and psychological damage to women, their fetuses, and their families. The psychological trauma includes a high rate of suicidal ideation as well as posttraumatic stress disorder. Whereas the healthcare costs are substantial for the mother with HG, the lifetime costs to the neonate include that which accompanies reduced employment earnings related to cognitive compromise. Another devastating outcome of severe HG can be Wernicke's encephalopathy (WE), which has a high fetal and maternal mortality rate. Our study explored 18 current reports of HG and WE. We highlighted additional presenting features we believe also accompany, and sometimes replace, the classically taught triad components of WE: ataxia, confabulation, and nystagmus. We agree with the conclusion made by Sheehan and Ironside in 1939 that thiamin alone may not reverse WE, and we offer possible explanations. Lastly, we offer suggestions for remediation.

Nausea and vomiting during pregnancy: A prospective study of its frequency, intensity, and patterns of change

OBJECTIVE

Our purpose was to provide a detailed description of patterns of nausea and vomiting of pregnancy.

STUDY DESIGN

A prospective study was performed with 160 women who provided daily recordings of frequency, duration, and severity of nausea and vomiting.

RESULTS

Seventy-four percent of women reported nausea lasting a mean of 34.6 days. "Morning sickness" occurred in only 1.8% of women, whereas 80% reported nausea lasting all day. Only 50% of women were relieved by 14 weeks' gestation; 90% had relief by week 22. Data based on the McGill Nausea Questionnaire indicate that the nausea experienced by pregnant women is similar in character and intensity to the nausea experienced by patients undergoing cancer chemotherapy.

CONCLUSIONS

Traditional teachings about nausea and vomiting of pregnancy are contradicted by our findings. Standardized tools for measuring the distribution, duration, and intensity of nausea are applicable to the study of nausea and vomiting of pregnancy and could be used in clinical trials to assess palliative measures.

A risk-benefit assessment of pharmacological and nonpharmacological treatments for nausea and vomiting of pregnancy

Despite evidence of fetal safety, most antiemetics are contraindicated in pregnancy. We summarise a risk-benefit analysis of the literature on safety and effectiveness of pharmacotherapy and nontraditional therapy for nausea and vomiting of pregnancy (NVP) to provide evidence-based guidelines on the management of NVP. The medical literature was scanned for controlled studies on the human teratogenicity and effect of various antiemetics in pregnant women. Data were pooled based on drug/therapy class and summarised to determine relative risk with 95% confidence interval (for malformations and failure rates for NVP) and homogeneity (chi-square test). Evidence from controlled trials has demonstrated the safety and efficacy of the following drugs for the treatment of varying degrees of NVP: doxylamine/pyridoxine+/-dicycloverine (dicyclomine), antihistamine H1 receptor antagonists, and phenothiazines (as a group). However, pooled data for doxylamine/pyridoxine+/-dicycloverine, H1 antagonists and phenothiazines were not homogeneous. Other therapies, such as pyridoxine alone, metoclopramide, ondansetron and the corticosteroids may be beneficial in managing NVP. However, limited efficacy studies and the paucity of well-controlled safety studies may limit the use of some of these agents among patients not responsive to first-line agents. Well-controlled safety and effectiveness trials in patients with NVP are lacking for nonpharmacological treatments (e.g. acupressure). NVP can be managed safely and effectively. Further trials must be conducted in order to determine the true effectiveness of certain agents in patients with NVP.

Nausea and vomiting of pregnancy

NVP is a spectrum of disorders ranging from the physiologically typical mild to moderate nausea and vomiting that is usually self-limited, to the pathologic, intractable symptoms of hyperemesis gravidarum that are associated with metabolic and electrolyte disturbances and weight loss. Up to 90% of pregnant women experience NVP. The pathogenesis remains poorly understood with multifactorial theories proposed combining both biologic and psychological factors. Diagnosing this syndrome is straightforward, but other organic sources should be excluded when symptoms are severe or prolonged. The overall prognosis is excellent for typical NVP, but whether hyperemesis gravidarum increases the risk to the fetus is controversial. Initial management should be conservative, including reassurance of the transient nature of the symptoms and the good prognosis, in addition to dietary modifications. Pharmacologic therapy is reserved for patients with persistent symptoms and is appropriate after discussion of the risks and benefits with informed consent. Alternative treatments, including psychotherapy and other nonpharmacologic modalities, are less proven but potentially safe and effective, thus providing additional therapeutic options. In refractory cases, nutritional supplementation becomes life-saving for both the mother and the fetus. Therapeutic abortion is a rare and last resort, to be used only when maternal life is threatened.

Hyperolfaction and hyperemesis gravidarum: what is the relationship?

The exact etiology of hyperemesis gravidarum (pernicious vomiting of pregnancy) is unknown, but hyperolfaction may be one contributing factor. The net result of hyperolfaction in pregnancy may be a mechanism cuing the pregnant woman to seek a cleaner, quieter, more temperate environment.

Clinical advances in the management of severe nausea and vomiting during pregnancy

The nutritional status of the woman with hyperemesis of pregnancy has been compromised by decreased food intake and increased nutrient loss. Depending on the severity of symptoms, interventions may begin with dietary and life-style alterations, proceed to oral nutritional supplementation or pharmacologic preparations, and continue on to intravenous vitamin-mineral therapy and either enteral tube feedings, parenteral nutrition, or both. These therapies, and the role of the nurse in initiating or supporting them, are described.