A severe kind of hypoxia (lack of oxygen) affecting a baby in the period just before, during, and after delivery. For physiological reasons not fully understood, babies can generally survive temporary loss of oxygen better than an older child or adult can; that allows them to survive the usually brief period between the time the placenta separates from the uterus wall and the time the newly born infant begins to breathe independently. Even so, perinatal asphyxia is a leading cause of death both in the fetus and in newborns. Babies may be at risk for perinatal asphyxia when labor is long and difficult, when fetal presentation (position at birth) is abnormal, when the placenta separates prematurely, with Rh incompatibility of the mother and fetus’s blood types, with long-standing high blood pressure in the mother, and in multiple births. Obstetricians often check fetal position and heartbeat, as with fetal monitors, looking for early warning signs of fetal distress, including perinatal asphyxia. Infants with this oxygen starvation often gasp for breath or do not breathe at all {apnea) and have slow heartbeat {bradycardia), limited activity, low body temperature, pale color or blueness (cyanosis), and abnormally high levels of hydrogen in the body {acidosis). An asphyxiated infant receives immediate resuscitation, often including pure oxygen poured into the air passages through a tube; cardiac massage; and various medications, depending on the analysis of blood samples from the infant. One of the main reasons for women with high-risk pregnancies to give birth at high-level hospitals, such as regional medical centers, is that these hospitals are best equipped to deal with asphyxia. Even with the best treatment, however, many babies who survive may have serious complications affecting one or more of the main systems of the body.