Prematurity may be caused by other known complications associated with AS such as IUGR. Depending on the extent of prematurity, such birth defects could include neurological problems (eg. cerebral palsy, apnea of prematurity, retinopathy of prematurity), respiratory problems (eg. respiratory distress syndrome), cardiovascular problems (eg. patent ductus arteriosus), gastrointestinal/metabolic diso