Hyperbilirubinemia causes jaundice in babies. Extra red blood cells from fetal circulation are broken down by the liver when a newborn begins breathing air. This process creates bilirubin, which gives the skin a yellow pigment within a few days of birth. Most term newborns do not require treatment, but bilirubin levels in the blood that rise too early, become too high or last too long can cause brain damage. Some associated fetal risks may increase the likelihood of more severe types of jaundice. Treatment usually consists of light therapy and fluids. Sometimes, blood transfusions are necessary.
Preterm Birth
A common cause of hyperbilirubinemia is preterm labor and birth. Maternal infections that threaten the fetus, such as trichomonas or group B Streptococcus, may cause the bag of waters to rupture, triggering labor before the infant is ready to be born. A baby that is less than 37 weeks gestation is at increased risk of hyperbilirubinemia because of his immature liver, which cannot change bilirubin into a form that can be easily eliminated. The Mayo Clinic lists other causes of preterm birth, such as multiple gestation, maternal diabetes and poor nutrition. Preterm labor and birth are also associated with smoking, drinking and drug use during pregnancy.
Blood Incompatibility
A serious threat to the fetus for hyberbilirubinemia is antibodies in the mother's blood that attack the red blood cells of her developing baby. The condition, known as Rh disease, occurs when the mother's Rh negative blood comes in contact with Rh positive blood, usually during the birth of her first child. Sensitization then becomes worse with each subsequent pregnancy. Affected infants develop anemia and early jaundice and may require a blood transfusion to survive. Rh disease was a common cause of pregnancy loss and neonatal death until Rh immune globulin became available in 1968, according to Johnson and Johnson, the makers of Rhogam. The injection is now routinely given to all Rh negative women following birth or pregnancy loss to prevent antibody formation. A less serious blood incompatibility may occur between a mother who has O positive blood and a fetus with type A or B blood.
TORCH Infections
An acronym for contagious diseases that pose serious health risks to the fetus, TORCH stands for toxoplasmosis, cytomegalovirus, rubella and herpes simplex. The O stands for other, including syphilis, HIV, mumps, human parvovirus and varicella, or chicken pox. Many of these illnesses are typically experienced in childhood, conferring maternal immunity, or the mother has received vaccines. Others may be recurrent, but are most dangerous when contracted for the first time during pregnancy. Besides the risk of neonatal hyperbilirubinemia, fetal growth and development may be affected by TORCH infections, sometimes resulting in pregnancy loss or life-long disability. "American Family Physicians" published an article in May 2008 that states the type of hyperbilirubinemia produced by TORCH infections consists primarily of conjugated bilirubin, a water soluble form which has been processed by the infant's liver and is easier to eliminate. Unconjugated bilirubin, a fat soluble form that is more toxic to brain tissue, is the type associated with blood incompatibilities.
