<prompt> Most important risk factor for neonatal respiratory distress syndromeDiabetic motherAsphyxiaPrematurityTwin pregnancy  <response>: Hyaline membrane disease HAM or respiratory distress syndrome RDS HMD always occurs in preterm babies often less than 34 weeks of gestation.It is the commonest cause of respiratory distress in a preterm neonate.Predisposing factors for HMD are -- Prematurity most important, asphyxia, acidosis, maternal diabetes, multiple birth, cesarean section delivery, cold stress and a history of previously affected infants.Incidence is highest in preterite male and white infant.Risk is reduced in pregnancies with pregnancy associated hypertension, maternal heroin use, prolonged rupture of membranes, and antenatal carticosteroid prophylaxis. 