Infantile respiratory distress syndrome (IRDS), also called respiratory distress syndrome of newborn, or increasingly surfactant deficiency disorder (SDD), and previously called hyaline membrane disease (HMD), is a syndrome in premature infants caused by developmental insufficiency of pulmonary surfactant production and structural immaturity in the lungs. It can also be a consequence of neonatal infection and can result from a genetic problem with the production of surfactant-associated proteins. IRDS affects about 1% of newborns and is the leading cause of death in preterm infants. Data has shown the choice of elective caesarean sections to strikingly increase the incidence of respiratory distress in term infants; dating back to 1995, the UK first documented 2,000 annual caesarean section births requiring neonatal admission for respiratory distress. The incidence decreases with advancing gestational age, from about 50% in babies born at 26–28 weeks to about 25% at 30–31 weeks. The syndrome is more frequent in males, Caucasians, infants of diabetic mothers and the second-born of premature twins. IRDS is distinct from pulmonary hypoplasia, another leading cause of neonatal death that involves respiratory distress. Signs and symptoms IRDS begins shortly after birth and is manifested by fast breathing (more than 60 breaths per minute), a fast heart rate, chest wall retractions (recession), expiratory grunting, nasal flaring, and blue discoloration of the skin during breathing efforts. As the disease progresses, the baby may develop ventilatory failure (rising carbon dioxide concentrations in the blood) and prolonged cessations of breathing ("apnea"). Whether treated or not, the clinical course for the acute disease lasts about two to three days. During the first day, the child worsens and requires more support. During the second day, the baby may be remarkably stable on adequate support and resolution is noted during the third day, heralded by a prompt diuresis. Despite huge advances in care, IRDS remains the most common single cause of death in the first month of life in the developed world. Complications include metabolic disorders (acidosis, low blood sugar), patent ductus arteriosus, low blood pressure, chronic lung changes and bleeding in the brain. The syndrome is frequently complicated by prematurity and its additional effect on other organ functions. Related disorders Acute respiratory distress syndrome (ARDS) has some similarities to IRDS. Transient tachypnea of the newborn presents with respiratory distress syndrome in the Term child. Histopathology The characteristic histopathology seen in babies who die from RDS was the source of the name