Wilford Hall conducts study to reduce premature births
Lt. Col. (Dr.) Andrea Shields performs an ultrasound on a patient June 21, 2010 in the Wilford Hall Medical Center at Lackland Air Force Base, San Antonio, while explaining the benefits of her pre-term birth study. Doctor Shields is a maternal-fetal medicine specialist. (U.S. Air Force photo/Senior Airman Josie Walck)