Nausea in pregnant women can be a sign of flu: Researchers

Nausea in pregnant women tends to fade after the first three months, but during the second and third trimesters it can be a sign of flu, researchers at UT Southwestern Medical Center have found in a study of expectant women who sought medical care.

"People don't necessarily think of influenza when you include the symptoms of nausea or vomiting, but our study showed that they are common with influenza in pregnancy," said Dr. Vanessa Rogers, assistant professor of obstetrics and gynecology and lead author of the study, which appears in the May edition of Obstetrics and Gynecology.

"Both physicians and patients should be aware of these findings so treatment is not delayed," she said. "I think our findings should encourage people to be vigilant and to take symptoms seriously."

Adults with flu tend not to have nausea or vomiting, according to the Centers for Disease Control and Prevention. These symptoms are more typical in children.

The researchers studied the cases of pregnant women during the 2003-2004 flu season, when the most common strain of influenza caused more severe symptoms than usual. There also were more cases of flu than expected, because the vaccine given that year didn't match the strain that was predominant.

During that period, 107 pregnant women were diagnosed with flu at Parkland Memorial Hospital in Dallas. Ninety-three percent of the women had a cough, and 89 percent had fever - common signs of flu - the researchers found. Eighty-five percent had a "profound" elevated heart rate, and 60 percent had nausea and/or vomiting. Although "morning sickness" and nausea are common during pregnancies, the researchers said that reporting any unusual additional symptoms (fever, coughing, elevated heart rate) could help diagnose the disease earlier in these patients.

Nearly two-thirds of the expectant women treated at Parkland were sick enough to require hospitalization. The most common complication was pneumonia, which occurred in 12 percent of the cases.

Despite the illness, there was no significant difference in complications between women with flu and women without flu who gave birth at the hospital during flu season. After birth, the babies also showed no significant difference in complications.

"Early diagnosis and treatment might be the reason our patients did so well," Dr. Rogers said.