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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Nausea and Vomiting in Pregnancy
Sponsored by The Indian Health Service Clinical Support Center
2. Background
Clinical Features
There are several classic features of hyperemesis
gravidarum.
It presents early in the first trimester of pregnancy, usually
in the fourth to tenth week of gestation, with intractable vomiting. Many patients
have weight loss exceeding 5 percent of their body weight. Abdominal pain is
infrequent.
Patients may present with ketosis and electrolyte derangements such as hypokalemia and metabolic alkalosis. There is often an increase in hematocrit, indicating hemoconcentration due to plasma volume depletion. The degree of hemoconcentration may be underestimated unless the decline in hematocrit seen in normal pregnancies is considered. Abnormal liver enzymes may also be present.
Risk factors
Studies of the risk factors for hyperemesis gravidarum have been small, and
results not always definitive. Advanced maternal age (age >35) and cigarette
smoking (perhaps due to the effect of nicotine may be protective. An association
with gestational
trophoblastic disease
has been well-described.
Non-pregnant women who experience nausea and vomiting after estrogen exposure, from motion sickness, with migraine, or with exposure to certain tastes (supertasters) are more likely to have pregnancy-related nausea and vomiting. In contrast, anosmic women appear to be at low risk for this disorder.
