Premature infants are at greater risk for developing

A premature newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, premature newborns have underdeveloped organs, which may not be ready to function outside of the uterus.

• A previous premature birth, multiple births, poor nutrition during pregnancy, late prenatal care, infections, assisted reproductive techniques (such as in vitro fertilization), and high blood pressure can increase the risk of a premature birth.

• Because many organs are underdeveloped, premature newborns may have difficulty breathing and feeding and are prone to bleeding in the brain, infections, and other problems.

• The earliest and smallest premature newborns are at far greater risk of having problems, including developmental problems.

• Although some premature newborns grow up with permanent problems, the majority of survivors are normal.

• Early prenatal care may decrease the risk of a premature birth.

• Premature birth can sometimes be delayed for a brief period by giving the mother drugs to slow or stop contractions.

• When an infant is expected to be delivered significantly early, doctors can give the mother injections of a corticosteroid to speed the development of the fetus’s lungs and help prevent bleeding in the brain (intraventricular hemorrhage).

Gestational age refers to how far along the fetus is. The gestational age is the number of weeks between the first day of the mother's last menstrual period and the day of delivery. This time frame is often adjusted according to other information doctors receive, including the results of early ultrasound scans, which give additional information regarding the gestational age. The baby is estimated to be due (the due date) at 40 weeks of gestation.

Newborns are classified by gestational age as premature if they are delivered before 37 weeks of gestation. Premature infants are further categorized as

• Extremely preterm: Delivered before 28 weeks of gestation

• Very preterm: Delivered at 28 to before 32 weeks of gestation

• Moderately preterm: Delivered at 32 to before 34 weeks of gestation

• Late preterm: Delivered at 34 to before 37 weeks of gestation

About 1 of every 10 infants born in the United States is born before full term. Greater degrees of prematurity are associated with greater risks of serious and even life-threatening complications.

Extreme prematurity is the single most common cause of death in newborns. Also, newborns born very prematurely are at increased risk of long-term problems, especially delayed development Definition of Developmental Disorders Developmental disorders are better called neurodevelopmental disorders. Neurodevelopmental disorders are neurologically based conditions that can interfere with the acquisition, retention, or... read more , cerebral palsy Cerebral Palsy (CP) Cerebral palsy refers to a group of symptoms that involve difficulty moving and muscle stiffness (spasticity). It results from brain malformations that occur before birth as the brain is developing... read more , and learning disorders Learning Disorders Learning disorders involve an inability to acquire, retain, or broadly use specific skills or information, resulting from deficiencies in attention, memory, or reasoning and affecting academic... read more . Nonetheless, most infants who are born prematurely grow up with no long-term difficulties.

The causes of premature birth are frequently unknown. However, there are many known risk factors for premature birth. Adolescents and older women, women of lower socioeconomic status, and women who have less formal education are at increased risk of premature birth.

Risk factors from a previous pregnancy:

• Previous premature birth (biggest risk factor)

Risk factors before or during pregnancy:

• Multiple fetuses conceived naturally

• Little or no prenatal care

• Cigarette smoking

• Untreated infections during pregnancy Infections During Pregnancy Most common infections that occur during pregnancy, such as those of the skin, urinary tract, and respiratory tract, cause no serious problems. However, some infections can be passed to the... read more , such as urinary tract infections Infections During Pregnancy Most common infections that occur during pregnancy, such as those of the skin, urinary tract, and respiratory tract, cause no serious problems. However, some infections can be passed to the... read more , sexually transmitted infections Infections During Pregnancy Most common infections that occur during pregnancy, such as those of the skin, urinary tract, and respiratory tract, cause no serious problems. However, some infections can be passed to the... read more , or infection of the uterus (intra-amniotic infection Intra-Amniotic Infection Intra-amniotic infection is infection of the tissues around the fetus, such as the fluid that surrounds the fetus (amniotic fluid), the placenta, the membranes around the fetus, or a combination... read more )

However, most women who deliver a premature newborn have no known risk factors.

Early prenatal care may decrease the risk of premature birth.

Premature newborns usually weigh less than 5½ pounds (2.5 kilograms), and some weigh as little as 1 pound (½ kilogram). Symptoms often depend on immaturity of various organs.

The immune system in any premature newborn is also underdeveloped, and therefore premature newborns are prone to infections.

Most complications of prematurity are caused by underdeveloped and immature organs and organ systems. The risk of complications increases with the degree of prematurity. Risk of complications also depends in part on the presence of certain causes of prematurity, such as infection, diabetes, high blood pressure, or preeclampsia.

Several problems arise when an infant is born before the brain is fully developed. These problems include

• Difficulty coordinating feeding and breathing: The parts of the brain that control reflexes involving the mouth and throat are immature, so premature newborns may not be able to suck and swallow normally, resulting in difficulty coordinating feeding with breathing.

An underdeveloped digestive tract and liver can cause several problems, including the following:

• Frequent episodes of not tolerating feedings: The intestines of premature newborns move very slowly, and premature newborns frequently have difficulty passing stools. Because of the slow movement of the intestinal tract, premature infants do not easily digest the breast milk or formula they are given.

The lungs of premature newborns may not have had enough time to fully develop before birth. The tiny air sacs called alveoli that absorb oxygen from the air and remove carbon dioxide from the blood are not formed until about the beginning of the last third of pregnancy (3rd trimester). In addition to this structural development, the tissues of the lungs must make a fatty material called surfactant. Surfactant coats the inside of the air sacs and allows them to remain open throughout the breathing cycle, making it easy to breathe. Without surfactant, the air sacs tend to collapse at the end of each breath, making breathing very difficult. Usually, the lungs do not make surfactant until about 32 weeks of pregnancy, and production is typically not adequate until about 34 to 36 weeks.

There is no treatment to make the lung structure mature more rapidly, but with adequate nutrition, the lungs continue to mature over time.

There are two approaches to increase the amount of surfactant and reduce the likelihood and severity of respiratory distress:

• Before birth: Corticosteroid drugs such as betamethasone increase surfactant production in the fetus and are given to the mother by injection when a premature delivery is anticipated, typically 24 to 48 hours before delivery.

• After birth: Doctors may give surfactant directly into the newborn's windpipe (trachea).

Premature newborns are also prone to developing high blood sugar levels (hyperglycemia) if they have an infection or bleeding in the brain or receive too much glucose intravenously. However, hyperglycemia rarely causes symptoms and can be controlled by limiting the amount of glucose given to the newborn or by using insulin for a short period of time.

A common issue among less mature infants is a patent ductus arteriosus Patent Ductus Arteriosus In patent ductus arteriosus (PDA), the blood vessel connecting the pulmonary artery and the aorta (ductus arteriosus) fails to close as it usually does shortly after birth. Patent ductus arteriosus... read more

• Appearance of the newborn

• Gestational age

• Birthweight

• Degree of prematurity

• Whether the mother was given corticosteroids for 24 to 48 hours before a premature delivery

• Complications that arise after birth

The sex of the baby also affects the likelihood of a good outcome: girls have a better prognosis than boys who have the same degree of prematurity.

Survival itself is rare if infants are born at less than 23 weeks of gestation. Infants born at 23 to 24 weeks may survive, but few have normal neurologic function. Most infants born after 27 weeks of gestation survive with normal neurologic function.

• Treatment of complications

Very premature newborns may require a drug that prompts them to breathe, such as caffeine, until the part of the brain that controls regular breathing has matured.

To keep warm, these newborns need to be kept in an incubator until they are able to maintain a normal body temperature.

Extremely premature newborns require all the same care as very premature newborns. Like very premature newborns, these newborns cannot be released from the hospital until they are able to breathe on their own, take oral feedings, maintain a normal body temperature, and gain weight.

Premature infants typically remain hospitalized until their medical problems are under satisfactory control and they are

• Taking an adequate amount of milk without special assistance

• Gaining weight steadily

• Able to maintain a normal body temperature in a crib

• No longer having pauses in breathing (apnea of prematurity)

Most premature infants are ready to go home when they are at 35 to 37 weeks of gestational age and weigh 4 to 5 pounds (2 to 2.5 kilograms). However, there is wide variation. The length of time the infant stays in the hospital does not affect the long-term prognosis.

Because premature newborns are at risk of stopping breathing (apnea), and having low levels of oxygen in the blood and a slow heart rate while in a car seat, many hospitals in the United States do a car seat challenge test before premature babies are discharged. The test is done to determine whether babies are stable in the semi-reclined position of a car seat. This test is usually done using the car seat provided by the parents. The car seat challenge test is not highly accurate and is not used by doctors in some other countries. Premature babies, including those who pass the test, should be observed by a non-driving adult during all car seat travel until the babies have reached the due date and have remained consistently able to tolerate being in the car seat. Because the baby's color should be observed, travel should be limited to daylight hours. Long trips should be broken up into 45- to 60-minute segments so that the baby can be taken out of the car seat and repositioned.

Surveys show that most car seats are not installed optimally, so a check of the car seat by a certified car seat inspector is recommended. Inspection sites can be found here. Some hospitals offer an inspection service, but casual advice provided by an uncertified hospital staff member should not be considered equivalent to inspection by a certified car seat expert.

The American Academy of Pediatrics recommends that car seats be used only for vehicular transportation and not as an infant seat or bed at home. Many doctors also recommend that parents do not put premature infants in swings or bouncy seats for the first few months at home.

After discharge, premature infants are carefully monitored for developmental problems and receive physical, occupational, and speech and language therapy as needed.

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

• Safe to Sleep®: Information for parents and caregivers about safe sleep practices for infants

• National Highway Traffic Safety Administration: Child car seat inspection station locator: Information about where to get an installed car seat inspected or where to get help with installation