A "concerning" decline in blood donations since last month could put stress on U.S. blood supplies through the American Red Cross. And the organization worries the number of blood donations will only continue to go down."Last month, we collected over 26,000 fewer blood donations than needed to meet the needs of patients,” Tiffany Taylor, a biomedical communications specialist for the American Red Cross, said.It comes with the time of year — more people are traveling and fewer blood drives are being held in places like schools. But Taylor said the need for blood doesn't take a summer break. "When blood donations are low, this can lead to blood shortages and which affect our ability to support cancer patients in their treatment,” Taylor said. “It affects our ability to respond to medical emergencies and chronic blood conditions that require blood transfusions."If blood isn't readily available, it can also lead to the postponement of elective surgeries. Taylor said low donations are especially concerning for the approximately 100,000 Americans who suffer from sickle cell disease. “There is no widely available cure and they often rely on regular blood transfusions to manage their pain and prevent life-threatening complications,” Taylor explained.While donors of all blood types are needed, the Red Cross is especially in need of Type O, which is always in high demand.Watch the video above for more on this story.