CDC changes Zika virus guidance for pregnant women

Federal health officials are changing their testing recommendations for pregnant women who may be exposed to the Zika virus through travel or sex or because of where they live.

In updated guidance released Monday, the Centers for Disease Control and Prevention is no longer recommending routine testing for pregnant women without any Zika symptoms but who may have been put at risk because they live in a region with ongoing exposure or have traveled to a region where Zika is circulating.

The new guidance should not be seen as a sign that Zika infections are any less dangerous for pregnant women, experts said. Instead, the revised recommendations reflect the limitations of the most commonly used blood test for the virus. In recent months, CDC has seen a growing number of false-positive test results from states.

Yet officials emphasized that pregnant women with possible Zika exposure and symptoms should continue to be tested as soon as possible after those begin. Symptoms include fever, rash, headache, joint pain and red eyes.

The change in recommendations is raising concern for some obstetricians, who worry that infections will get missed because of the de-emphasis on routine testing for some asymptomatic pregnant women.

Many people infected with Zika Laura Riley, vice chair of the obstetrics department at Massachusetts General Hospital, said specialists at the American College of Obstetricians and Gynecologists and the Society for Maternal Fetal Medicine worked with CDC on the latest update.

Any change in guidance is likely to be confusing at first, she acknowledged. But the test in question "is not quite as specific as we were hoping," she said. "When the disease incidence decreases, the test performs even worse than it did when there was lots of disease. What the patient then gets is a potentially false positive, and that creates nothing but hysteria."

In places like Florida and Texas, which have had local transmission and see much travel with Zika-affected regions, local and state health departments may want to enhance their screening of asymptomatic pregnant women, CDC officials said.