Before your baby leaves the hospital, a small amount of his or her blood will be taken and sent to the state health department or a private laboratory working in collaboration with the state laboratory. This sample, which may be taken from a tiny poke on the heel (most common) or from a vein in your baby’s arm, is analyzed to detect the presence of rare but important genetic diseases. This testing is referred to as newborn screening.
The purpose of the testing is to identify babies who might be at risk and enable families to access relevant treatment and resources early. Results are generally available in one to two weeks. Occasionally, a baby needs to have the test repeated. Don’t be alarmed if this happens to your newborn. To ensure that every newborn with any of these conditions is identified, even borderline results are rechecked. Retesting is especially common for premature babies.
Each state independently operates its newborn screening program, resulting in slight differences between the tests offered. Current national recommendations include a panel of tests to check for 35 core disorders and 26 secondary disorders. Some states check for additional diseases. You also may request a specific genetic test if you feel your child may be at risk of a certain genetic disorder.
Some of the diseases that can be detected by the panel include:
Congenital adrenal hyperplasia (CAH) —This group of disorders is caused by a deficiencyof certain hormones. Signs andsymptoms may include lethargy, vomiting,muscle weakness and dehydration.Infants with mild forms are at risk of reproductiveand growth difficulties. Severecases can cause kidney dysfunction andeven death. Lifelong hormone treatmentcan suppress the condition.
Congenital hypothyroidism — About 1 in 3,000 babies has a thyroid hormone deficiency that slows growth and brain development. Left untreated, it can result in mental retardation and stunted growth. With early detection and treatment, healthy development is possible.
Cystic fibrosis — Cystic fibrosis causes the body to produce abnormally thickened mucous secretions in the lungs and digestive system. Signs and symptoms generally include salty-tasting skin, poor weight gain, and, eventually, persistent coughing and shortness of breath. Affected newborns can develop life-threatening lung infections and intestinal obstructions. With early detection and treatment, infants diagnosed with cystic fibrosis now often live longer and in better health than infants diagnosed in the past.
Galactosemia — Babies born with galactosemia can’t metabolize a sugar found in milk (galactose). Although newborns with this condition typically appear otherwise healthy, they may develop vomiting, diarrhea, jaundice and liver damage within a few weeks of their first milk feedings. Left untreated, the disorder may result in mental disabilities, blindness, growth failure and, in severe cases, death. Treatment includes eliminating milk and all other dairy products from the diet.
Phenylketonuria (PKU) — Babies with PKU retain excessive amounts of phenylalanine — an amino acid found in the protein of almost all foods. Without treatment, PKU can cause mental and motor disabilities, poor growth rate, and seizures. With early detection and treatment, growth and development should be normal.
Sickle cell disease — This inherited disease prevents blood cells from circulating easily throughout the body. Infants with sickle cell disease experience an increased susceptibility to infection and slow growth rates. The disease can cause bouts of pain and damage to vital organs such as the lungs, kidneys and brain. With early medical treatment, the complications of sickle cell disease can be minimized.
While your baby is in the hospital, he or she may have a hearing test. Although hearing tests are not done routinely at every hospital, newborn hearing screening is becoming widely available. The testing can detect possible hearing loss in the first days of a baby’s life. If possible hearing loss is found, further tests may be done to confirm the results.
Two tests are used to screen a newborn’s hearing. Both are quick (about 10 minutes) and painless and can be done while your baby sleeps. One test measures how the brain responds to sound. Clicks or tones are played through soft earphones into the baby’s ears while electrodes taped on the baby’s head measure the brain’s response. Another test measures specific responses to sound waves that enter a baby’s ear. As clicks or tones are played into a baby’s ear, a probe placed inside the ear canal measures the response.
Critical congenital heart defect (CCHD) screening
Before leaving the hospital, your baby will likely also be screened for any heart defects. Ultrasounds can identify many heart defects during a pregnancy. However, some issues may be missed or cannot be detected until after a baby is born.
For this test, an oxygen sensor (pulse oximeter) is placed on your baby’s hands or feet. The test is quick and does not cause discomfort to your baby. If the oxygen levels are low or different on the right and left sides, your baby’s health care provider will most likely recommend additional testing.
Mayo Clinic Guide to Your Baby’s First Years, Second EditionShop Now