Pregnancy lasts approximately 38 to 42 weeks in humans. Babies born earlier than 37 weeks are considered premature. Depending on how early they arrive, these children may have lungs, a liver and a circulatory system that are unprepared for life outside the uterus. Premature infants can have trouble breathing and carrying on metabolic processes. Intensive care measures can help even tiny babies survive even though they are prone to many diseases.
Lung Disease
Respiratory distress syndrome (RDS) is common in premature infants because their lung surfaces lack the substance surfactant that allows airways to open and remain open. At about 31 weeks gestational age, the fetal lungs begin to mature but are not capable of functioning well outside the womb until for approximately another four weeks. Children's Hospital of Orange County states that premature infants exhibiting the labored breathing of RDS typically get worse in the first 48 to 72 hours after birth, when airways collapse and are blocked with inflammation and dead cells. Improvement follows with treatment, which may include oxygen, intubation, administration of surfactant and mechanical ventilation. Women at risk for preterm birth will be given corticosteroid medications by injection that stimulate the fetal lungs to mature and reduce the severity of RDS.
Patent Ductus Arteriosis
The ductus arteriosis is a blood vessel that connects the arteries leading from the heart to the lungs. While the fetus is dependent on the placenta for oxygen, less blood is pumped to the lungs. At birth, this connection closes to increase circulation to the airways as the baby takes his first breaths. If the ductus arteriosis remains patent, or open, the infant will demonstrate a rapid heart rate and respirations, tire easily, and have growth problems. Patent ductus arteriosis (PDA) is common in premature infants. Treatment depends on the size and severity of PDA; medications or surgery are sometimes necessary to correct the problem. In other instances, doctors decide to wait and see. The National Institutes of Health reports a high rate of spontaneous closure of PDA in premature infants during the first two years of life.
Hyperbilirubinemia
Also known as newborn jaundice, hyperbilirubinemia affects premature infants because the immature liver cannot completely eliminate wastes. While in the womb, the fetus needs extra red blood cells (RBCs) to carry oxygen from the placenta. Once the umbilical cord is severed, the infant's liver must destroy the excess RBCs. The waste from this process is bilirubin, which normally binds to breast milk and is excreted through the bowel or eliminated through the skin. The baby's complexion turns yellow as bilirubin builds up in the bloodstream. High levels of bilirubin can cause brain damage, or kernicterus. Treatment includes phototherapy, the use of bright lights to aid in the elimination of bilirubin. More aggressive treatment for hyperbilirubinemia involves blood transfusions. Neonatologists once thought phototherapy administered before the skin turns yellow would keep bilirubin levels lower, but a 2006 study published in the Indian Journal of Medical Science followed 100 babies over three months and did not attribute any significant benefits to prophylactic phototherapy.
