A flexible container for fluid administration is provided having a body defining a cavity, a base, and at least one port comprising a flange in contact with a flange of a terminal port having a punctureable membrane layer. The body has a cross-sectional configuration including a lower body section of a first dimension, a middle body section of a second dimension, and an upper body section of a third dimension, wherein the second dimension is smaller than the first dimension and the third dimension. The flexible container may also include a base having a plurality of creases that are foldable to form two folded ends each including an extension having a base of a first dimension and a tip of a second dimension.