Dr. Margaret Chan is director-general of the World Health Organization. In her first major address on Zika, delivered Thursday in Geneva, she said: "Questions abound. We need to get some answers quickly." Sandro Campardo//epa/Corbis hide caption

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U.S. health officials are telling pregnant women to avoid travel to Latin America and Caribbean countries with outbreaks of Zika, a tropical illness linked to birth defects. James Gathany/AP hide caption

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The FDA worries that the same alkaline treatment that gives corn masa its distinctive aroma and flavor might also prevent folic acid from remaining stable in masa. The agency is currently reviewing test results looking at the question of stability. Verónica Zaragovia for NPR hide caption

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Health inspectors collect samples of mosquito larvae from standing water in a garden in a middle-class neighborhood in the north of Rio de Janeiro. They are searching for places where the Aedes aegypti mosquito breeds — that's the one that carries Zika virus. Lourdes Garcia-Navarro/NPR hide caption

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Omar looks through Kai's photo book. The charges for the infant's six months of care in the neonatal intensive care unit totaled about $11 million, according to the family, though their insurer very likely negotiated a lower rate. Heidi de Marco/KHN hide caption

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Solid information on the risks of medications during pregnancy is often hard to come by. iStockphoto hide caption

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Ultrasound is often used for prenatal screening. It's just one of several prenatal screenings available to pregnant women. iStockphoto hide caption

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Jake and Natalie Peterson and their son Garrett in October 2014. Courtesy of Brittany Jacox hide caption

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Alice Snyder, with her parents Mary and Ryan, during a checkup with Dr. John Herzenberg, who treated her clubfoot without surgery. Jenny Gold/Kaiser Health News hide caption

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