Prematurity - Premature Infant

A premature infant is a baby who has spent less than 37 weeks in the womb. The average length of pregnancy is 40 weeks. So a premature infant is one who is born 3 weeks or more before the due date.

What is going on in the body?

Premature babies have not developed completely. The earlier a baby is born, the less developed its organs are. Premature babies tend to have very specific problems related to their underdeveloped organs. Sometimes the treatments that they receive for their underdeveloped organs also can lead to problems. For example, a baby born after only 24 weeks in the womb doesn't have fully developed lungs. Because of this it cannot breathe well on its own. It will probably need the help of an artificial breathing machine, or ventilator.

What are the causes and risks of the condition?

Certain factors in the mother are linked with the birth of a low-birth-weight infant. These factors include the following:

Some babies have factors themselves that make them more likely to be born early. These factors include being one of multiple babies in the same womb, such as twins or triplets. The baby may have physical problems or a bloodstream damaged by infection.

Sometimes there are problems with a mother's womb. The placenta may not be adequate to support the baby to full term. The placenta may be in an unusual location, such as placenta previa. When the mother has a chronic illness like diabetes, congestive heart failure, or high blood pressure, she is more likely to deliver early. Certain infections in the mother, such as genital herpes or Treponema pallidum\ bacteria. Less often, syphilis is transmitted from a pregnant woman to her baby. This form of syphilis is known as \congenital syphilis.\ ',CAPTION,'Syphilis');" onmouseout="return nd();">syphilis, can cause the baby to be born early.

What are the signs and symptoms of the condition?

The baby's weight at birth can help predict how well the baby will do. Babies whose birth weight is less than 2,500 grams, or about 5.5 pounds, are called low-birth-weight, or LBW, infants. LBW babies make up only 7% of births. However, they account for two-thirds of newborn deaths. Babies whose birth weight is less than 1,500 grams, or about 3.25 pounds, are called very-low-birth-weight, or VLBW, infants. These babies make up about 1% of births. They account for half of newborn deaths.

There are many problems associated with being born early. One of the problems is respiratory distress syndrome. This occurs when the baby's lungs are too underdeveloped to work properly. A baby with immature lungs may have trouble breathing and need a ventilator. Some babies cannot get enough oxygen, even with a ventilator. The ventilator can sometimes cause damage to the lungs. If high levels of oxygen have to be used, the baby can develop eye problems. Premature babies can have lifelong difficulties with breathing.

Another problem is that these babies have underdeveloped immune systems. That means they are not very good at fighting infection. They can develop severe and deadly infections, such as group B streptococcal septicemia, more easily than a normal newborn. Extremely premature babies usually need to be given antibiotics often and for long periods of time. Some of the antibiotics can cause long-term problems.

When babies are born very early, they can have bleeding in their brains. This can cause mild to severe brain damage. Many extremely premature babies do not develop normally as they grow up. It is hard to predict which babies will have development problems.

Premature babies can also have problems in the gut, the kidneys, or the liver. They can have trouble controlling the level of sugars and salts in their bloodstream. They often develop anemia and sometimes need blood transfusions to treat it.

How is the condition diagnosed?

Often, a woman knows how many weeks she has been pregnant. There are other ways to tell the age of the baby. The growth of the unborn baby can be estimated by examining the pregnant woman's womb. Pregnancy ultrasound is a test that uses sound waves. This test can be used to estimate the age of the unborn baby. After the baby is born, the healthcare provider can estimate the baby's age by doing a physical exam.

What can be done to prevent the condition?

Mothers may be able to lessen the chances of premature birth by avoiding some of the pregnancy risk factors. For example, prenatal care may help prevent a mother from having a premature baby. It is important to avoid drugs, alcohol, and smoking during pregnancy. But sometimes there is no way to prevent a baby from being born early.

What are the long-term effects of the condition?

Sometimes premature babies grow to be completely normal children. Over 90% of infants weighing more than 1,500 grams, or about 3 pounds, survive. But only about 40% of infants weighing less than 750 grams, or about 1.5 pounds, survive.

Of the babies who survive, 10% to 25% have mild developmental problems. Severe developmental problems occur in 5% to 10% of these babies. The smaller a baby is at birth, the more likely the baby is to have problems. The chronic problems that premature babies can develop often depend on what happens in the first few months after birth.

Premature birth or LBW also carries a higher risk of cerebral palsy and communication\ \education, including reading, writing, and basic math\ \motor function\ \personal care, such as bathing, dressing, eating, and toileting\ \social skills\ \thinking skills, such as decision making, problem solving, and self-direction\ \working\ ',CAPTION,'Mental Retardation');" onmouseout="return nd();">mental retardation. These babies can develop seizures as well. VLBW infants may have problems with learning and school performance.

What are the risks to others?

A premature baby is not contagious and poses no risk to others.

What are the treatments for the condition?

Treatment depends on how early a baby is born and its weight at birth. Babies who are born only a few weeks early usually just need time to grow, and time to learn to feed well. They often go home after a short time in the hospital. Usually, the earlier a baby is born, the longer it will stay in the hospital, and the more treatment it will need. The earlier a baby is born, the less likely it is to survive even with the best of care. The very premature babies who do survive often have to stay in a specialized hospital for several months.

What are the side effects of the treatments?

Ventilators may damage the baby's lungs. They also may cause chronic breathing problems. High levels of oxygen are sometimes needed to make sure the baby's organs get enough. This can have the side effect of damaging the blood vessels in the eyes. This in turn can cause poor vision. Certain antibiotics can cause trouble with hearing as the baby grows. Very premature babies often need to be fed through the bloodstream instead of through their guts. These babies can develop liver problems as a result.

What happens after treatment for the condition?

Once the baby is able to breathe on its own, he or she will usually spend some time in the nursery to grow more before going home. When the baby reaches a certain weight, the baby can go home and the parents can try to resume a normal life. But the baby may still need more care than a baby born on time. During the first year, the parents may spend more time in doctor visits with their baby than parents of babies who are not premature.

How is the condition monitored?

Babies who are born early usually are carefully monitored, especially for the first year. Very premature babies will be seen by eye and hearing specialists. They will be taken care of by development specialists and breathing specialists. Teams of healthcare providers work together to give these babies as much care as they need to help them develop as normally as possible. Any new or worsening symptoms should be reported to the healthcare provider.

Author:Lama Rimawi, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:07/31/01
Reviewer:Celia Buckley, RN, MSN
Date Reviewed:07/01/01

Sources