Premature birth
Premature birth

What is premature birth?

Birth is considered premature, or preterm, when it occurs before the 37th week of pregnancy. A normal pregnancy lasts about 40 weeks. Premature birth gives the baby less time to develop in the womb. Premature babies, especially those born earliest, often have complicated medical problems.

Depending on how early a baby is born, he or she may be:

  • Late preterm, born between 34 and 36 weeks of pregnancy.
  • Moderately preterm, born between 32 and 34 weeks of pregnancy.
  • Very preterm, born at less than 32 weeks of pregnancy.
  • Extremely preterm, born at or before 25 weeks of pregnancy.

Most premature births occur in the late preterm stage.

What are the causes of premature birth?

The cause of a premature birth often can't be identified. However, certain factors are known to increase a woman's risk of going into labor early. A pregnant woman with any of the following conditions is more likely to have a premature birth:

  • Diabetes.
  • Heart disease.
  • Kidney disease.
  • High blood pressure.

Different pregnancy-related problems increase the risk of preterm labor or early delivery includes:

  • Poor nutrition right before and during pregnancy.
  • Smoking, using illegal drugs during pregnancy.
  • Certain infections, such as urinary tract and amniotic membrane infections.
  • History of Premature birth.
  • An abnormal uterus.
  • A weakened cervix that begins to open (dilate) early, also called cervical incompetence.
  • Preeclampsia: high blood pressure and protein in the urine that develop after the 20th week of pregnancy.
  • Premature rupture of the membranes.

Pregnant women also have an increased chance of delivering early if they are younger than 17 or older than 35.

What are the symptoms of premature birth?

A premature birth means that your baby hasn't had the usual amount of time to develop in the womb before needing to adapt to life outside the womb. The signs that a baby's gestation has been cut short include:

  • Small size, with a disproportionately large head.
  • Sharper looking, less rounded features than a full-term baby's features, due to a lack of fat stores.
  • Fine hair (lanugo) covering much of the body.
  • Low body temperature, especially immediately after birth in the delivery room, due to a lack of stored body fat.
  • Labored breathing or respiratory distress.
  • Lack of reflexes for sucking and swallowing, leading to feeding difficulties.

What is the risk factor of premature birth?

  • Having a previous premature birth.
  • Pregnancy with twins, triplets or other multiples.
  • An interval of less than six months between pregnancies.
  • Conceiving through in vitro fertilization.
  • Problems with the uterus, cervix or placenta.
  • Smoking cigarettes or using illicit drugs.
  • Poor nutrition.
  • Not gaining enough weight during pregnancy.
  • Some infections, particularly of the amniotic fluid and lower genital tract.
  • Some chronic conditions, such as high blood pressure and diabetes.
  • Being underweight or overweight before pregnancy.
  • Stressful life events, such as the death of a loved one or domestic violence.
  • Multiple miscarriages or abortions.
  • Physical injury or trauma.

What are the complications of premature birth?

While not all premature babies experience complications, being born too early can cause short-term and long-term health problems for preemies. Generally, the earlier a baby is born, the higher the risk of complications. Birth weight plays an important role, too. Some problems may be apparent at birth, while others may not develop until later.

Short-term complications

In the first weeks, the complications of premature birth may include:

  • Breathing problems: A premature baby may have trouble breathing due to an immature respiratory system. He or she may develop respiratory distress syndrome because the lungs can't expand and contract normally, may also develop chronic lung disease known as bronchopulmonary dysplasia. In addition, some preemies experience prolonged pauses in their breathing, known as apnea.
  • Heart problems: The most common heart problems premature babies experience are patent ductus arteriosus (PDA is a persistent opening between two major blood vessels leading from the heart) and low blood pressure (hypotension may require adjustments in intravenous fluids, medicines and sometimes blood transfusions.). While this heart defect often closes on its own, left untreated it can cause too much blood to flow through the heart and cause heart failure as well as other complications.
  • Brain problems: The earlier a baby is born, the greater the risk of bleeding in the brain, known as an intraventricular hemorrhage. Most hemorrhages are mild and resolve with little short-term impact. But some babies may have larger brain bleeding which causes permanent brain injury.
  • Temperature control problems: Premature babies can lose body heat rapidly; they don't have the stored body fat of a full-term infant and they can't generate enough heat to counteract what's lost through the surface of their bodies. If body temperature dips too low, hypothermia can result (can lead to breathing problems and low blood sugar levels).
  • Gastrointestinal problems: Preemies are more likely to have immature gastrointestinal systems, leaving them predisposed to complications such as necrotizing enterocolitis (serious condition, in which the cells lining the bowel wall are injured, can occur in premature babies after they start feeding). Premature babies who receive only breast milk have a much lower risk of developing it.
  • Blood problems: Preemies are at risk of blood problems such as anemia and infant jaundice. Anemia is a common condition in which the body doesn't have enough red blood cells.
  • Metabolism problems: Premature babies often have problems with their metabolism. Some preemies may develop an abnormally low level of blood sugar (hypoglycemia). This can happen because they typically have smaller stores of glycogen (stored glucose) than do full-term babies and because their immature livers have trouble converting stored glycogen into glucose.
  • Immune system problems: An underdeveloped immune system, common in premature babies, can lead to infection. Infection in a premature baby can quickly spread to the bloodstream causing sepsis, a life-threatening complication.

Long-term complications

In the long term, premature birth may lead to these complications:

  • Cerebral palsy: Cerebral palsy is a disorder of movement, muscle tone or posture that can be caused by infection, inadequate blood flow or injury to a preemie's developing brain either during pregnancy or while the baby is still young and immature.
  • Impaired cognitive skills: Premature babies are more likely to lag behind their full-term counterparts on various developmental milestones. Upon school age, a child who was born prematurely might be more likely to have learning disabilities.
  • Vision problems: Premature infants may develop retinopathy of prematurity, a disease that occurs when blood vessels swell and overgrow in the light-sensitive layer of nerves at the back of the eye (retina). Sometimes the abnormal retinal vessels gradually scar the retina, pulling it out of position. When the retina is pulled away from the back of the eye, it's called retinal detachment, a condition that, if undetected, can impair vision and cause blindness.
  • Hearing problems: Premature babies are at increased risk of some degree of hearing loss. All babies will have their hearing checked before going home.
  • Dental problems: Preemies who have been critically ill are at increased risk of developing dental problems, such as delayed tooth eruption, tooth discoloration and improperly aligned teeth.
  • Behavioral and psychological problems: Children who experienced premature birth may be more likely than full-term infants to have certain behavioral or psychological problems, such as attention-deficit/hyperactivity disorder (ADHD).
  • Chronic health issues: Premature babies are more likely to have chronic health issues some of which may require hospital care. Infections, asthma and feeding problems are more likely to develop or persist. Premature infants are also at increased risk of sudden infant death syndrome (SIDS).

What kind of test done for the premature child?

Common tests performed on a premature infant include:

  • Blood gas analysis to check oxygen levels in the blood.
  • Blood tests to check glucose, calcium, and bilirubin levels.
  • Chest x-ray.
  • Echocardiogram to check for problems with your baby's heart function. Ultrasound scan to check brain bleeding or fluid buildup or to examine the abdominal organs for problems in gastrointestinal track, liver or kidneys. Continuous cardiorespiratory monitoring (monitoring of breathing and heart rate).
  • Fluid input and output: tracks how much fluid your baby takes in through feedings and intravenous fluids and how much fluid your baby loses through wet or soiled diapers, blood draws and other tests.

Preventing premature birth

Getting prompt and proper prenatal care significantly reduces the chances of having a premature birth. Other important preventive measures include:

  • Eating a healthy diet before and during your pregnancy: Make sure to eat lot of whole grains, lean proteins, vegetables, and fruits. Taking folic acid and calcium supplements is also highly recommended.
  • Drinking lots of water every day: The recommended amount is eight glasses per day, but you'll want to drink more if you exercise.
  • Quitting smoking, using illegal drugs, or overusing certain prescription drugs: These activities during pregnancy may lead to a higher risk of certain birth defects as well as miscarriage.
  • Talk to your doctor if you're concerned about having a premature birth. Your doctor may be able to suggest additional preventive measures that can help lower your risk of giving birth prematurely.


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