Last spring, when her obstetrician suggested an ultrasound test to see if she was carrying more than one baby, Jennell Dickens prayed that she wasn't carrying twins. When an ultrasound technician examined her belly, counting two, three and four heartbeats, she steeled herself for quadruplets. That was before a radiologist entered the room and found another heartbeat. Dickens cried for two months. Yesterday, she was the picture of composure, smiling and laughing at the University of Maryland Medical Center just two days after delivering four girls and a boy 10 weeks early. They weighed a combined 11 pounds, 14 ounces....