Transient tachypnea of the newborn (also called retained fetal lung fluid, or wet lung) is a benign, self-limited condition seen primarily in full-term infants. It is believed to result from delay in the reabsorption of fetal pulmonary fluid. There is an association between delivery by cesarean section and the development of this condition, possibly because of the compression of the chest during vaginal delivery and the mechanical “wringing out” of fetal lung fluid.