An ultrasound image of the National Zoo's giant panda Mei Xiang is pictured in this handout photograph taken and released on August 19, 2015. Mei Xiang is believed to be carrying a developing fetus and could give birth in coming weeks, the Washington zoo said on Wednesday. Veterinarians detected a 1.6-inch (4-cm) fetus during a Wednesday ultrasound, the zoo said in a statement. REUTERS/Smithsonian's National Zoo/Handout via Reuters FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS