of 100% oxygen. Increasing the oxygen concentration to the mother has shown little effect on the fetus as hyperoxygenated blood does not perfuse the placental exchange site well. Underlying etiology of intrauterine hypoxia serves as a potential therapeutic target. If maternal preeclampsia is the underlying cause of fetal growth restriction (FGR) antihypertensive therapy and magnesium sulfate are potential therapies. Antihypertensive treatment is used to reduce blood pressure and prevent pulmonary edema and cerebral hemorrhages. An effective course of antihypertensive treatments should reduce blood pressure to below 160/110 mmHg. Magnesium sulfate acts as a vasodilator, reducing vascular resistance and protect the blood-brain barrier (BBB). The goal of these treatments is to prolong pregnancy and increase fetal survival. Each day gained by treatment in utero increases fetal survival and intact survival by 1%–2% up to 28 weeks gestation. Prevention Medical testing and care can be performed in order to prevent intrauterine hypoxia, though can be difficult. These tests don't directly detect hypoxia, but instead detects the general well-being of the baby and ensures that the baby is healthy since hypoxia causes a wide range of responses. These tests can include prenatal testing, such as fetal movement and amniotic fluid levels, Doppler examination, or fetal heart rate. Another risk factor is premature birth in which medical intervention, such as premature birth prevention or C-section delivery, can be used as prevention for intrauterine hypoxia. Studies have shown a connection between tetrahydrobiopterin (BH4) deficiency and hypoxia-ischemia brain injury, though further studies need to be done. Measuring fetal BH4 levels can be another way to look out for intrauterine hypoxia. During birth, birth asphyxia can occur in which cardiotocograph can be used to monitor the baby's health during labor. Epidemiology In the United States, intrauterine hypoxia and birth asphyxia were listed together as the tenth leading cause of neonatal death. Society IH/BA is also a causative factor in cardiac and circulatory birth defects the sixth most expensive condition, as well as premature birth and low birth weight the second most expensive and it is one of the contributing factors to infant respiratory distress syndrome (RDS) also known as hyaline membrane disease, the most expensive medical condition to treat and the number one cause of infant mortality. Medicolegal In the United States the National Practitioner Data Bank 2006 Annual Report obstetrics-related cases accounted for 8.7 percent of all 2006 physician Malpractice Payment Reports and had the highest