Premature birth is a birth that takes place more than three weeks before the baby's estimated due date. In other words, premature birth is one that occurs before the start of the 37th week of pregnancy.
Premature babies, especially those born very early, often have complicated medical problems. Typically, complications of prematurity vary. But the earlier your baby is born, the higher the risk of complications.
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Depending on how early a baby is born, he or she may be:
- Late preterm, born between 34 and 36 completed 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.
Signs and Symptoms of Premature Birth
Your baby may have very mild symptoms of premature birth or may have severe complications.
Some signs of prematurity include the following:
- 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
Risk factors for Premature birth
According to the mayo clinic, the specific cause of premature birth isn't clear. However, there are known risk factors for premature delivery, including:
- Having a previous premature birth
- Pregnancy with twins, triplets or other multiples
- An interval of fewer than six months between pregnancies
- Conceiving through in vitro fertilization
- Problems with the uterus, cervix or placenta
- Smoking cigarettes or using illicit drugs
- 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
Complications of Premature birth
While not all premature babies experience complications, being born too early can cause short-term and long-term health problems. 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.
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.
Premature babies may also develop a lung disorder known as bronchopulmonary dysplasia. In addition, some preterm babies may experience prolonged pauses in their breathing, known as apnea.
Heart problems. The most common heart problems premature babies experiences are patent ductus arteriosus (PDA) and low blood pressure (hypotension). PDA is a persistent opening between the aorta and pulmonary artery. While this heart defect often closes on its own, left untreated it can lead to a heart murmur, 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 that 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, an abnormally low core body temperature (hypothermia) can result.
Hypothermia in a premature baby can lead to breathing problems and low blood sugar levels. In addition, a premature infant may use up all of the energy gained from feedings just to stay warm. That's why smaller premature infants require additional heat from a warmer or an incubator until they're larger and able to maintain body temperature without assistance.
Gastrointestinal problems. Premature infants are more likely to have immature gastrointestinal systems, resulting in complications such as necrotizing enterocolitis (NEC). This potentially 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 NEC.
Blood problems. Premature babies are at risk of blood problems such as anemia and newborn jaundice. Anemia is a common condition in which the body doesn't have enough red blood cells. While all newborns experience a slow drop in red blood cell count during the first months of life, the decrease may be greater in premature babies.
Newborn jaundice is a yellow discoloration in a baby's skin and eyes that occurs because the baby's blood contains excess bilirubin, a yellow-colored substance, from the liver or red blood cells. While there are many causes of jaundice, it is more common in preterm babies.
Metabolism problems. Premature babies often have problems with their metabolism. Some premature babies may develop an abnormally low level of blood sugar (hypoglycemia). This can happen because premature infants typically have smaller stores of stored glucose than do full-term babies. Premature babies also have more difficulty converting their stored glucose into more-usable, active forms of glucose.
Immune system problems. An underdeveloped immune system, common in premature babies, can lead to a higher risk of infection. Infection in a premature baby can quickly spread to the bloodstream, causing sepsis, an infection that spreads to the bloodstream.
Long-term complications of premature birth
In the long term, premature birth may lead to the following 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 newborn's developing brain either early during pregnancy or while the baby is still young and immature.
Impaired learning. 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. Premature infants 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, as well as developmental delays.
Chronic health issues. Premature babies are more likely to have chronic health issues — some of which may require hospital care — than are full-term infants. 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).
Prevention of Premature Birth
Although the exact cause of preterm birth is often unknown, there are some things that can be done to help women — especially those who have an increased risk — to reduce their risk of preterm birth, including:
Progesterone supplements. Women who have a history of preterm birth, a short cervix or both factors may be able to reduce the risk of preterm birth with progesterone supplementation.
Cervical Cerclage. This is a surgical procedure performed during pregnancy in women with a short cervix or a history of cervical shortening that resulted in preterm birth.
During this procedure, the cervix is stitched closed with strong sutures that may provide extra support to the uterus. The sutures are removed when it's time to deliver the baby. Ask your doctor if you need to avoid vigorous activity during the remainder of your pregnancy.
Diagnosis of Premature Birth
After your premature baby is moved to the NICU, he or she may undergo a number of tests. Some are ongoing, while others may be performed only if the NICU staff suspects a particular complication.
Possible tests for your premature baby may include:
Breathing and heart rate monitor. Your baby's breathing and heart rate are monitored on a continuous basis. Blood pressure readings are done frequently, too.
Fluid input and output. The NICU team carefully 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 tests. In a Blood test lab, samples are collected through a heel stick or a needle inserted into a vein to monitor a number of critical substances, including calcium, glucose and bilirubin levels in your baby's blood. A blood sample may also be analyzed to measure the red blood cell count and check for anemia or assess for an infection.
If your baby's doctor anticipates that several blood samples will be needed, the NICU staff may insert a central umbilical intravenous (IV) line, to avoid having to stick your baby with a needle each time blood is needed.
Echocardiogram. This test is an ultrasound of the heart to check for problems with your baby's heart function. Much like a fetal ultrasound, an electrocardiogram uses sound waves to produce moving images on a display monitor.
Ultrasound scan. Ultrasound scans may be done to check the brain for bleeding or fluid buildup or to examine the abdominal organs for problems in the gastrointestinal tract, liver or kidneys.
Eye exam. An ophthalmologist (eye doctor) may examine your baby's eyes and vision to check for problems with the retina (retinopathy of prematurity).
If your baby develops any complications, other another specialized testing needed.
Treatment of Premature birth
Illustration showing a room in the intensive care unit Intensive care for your premature baby
The neonatal intensive care unit (NICU) or special care nursery provides round-the-clock care for your premature baby.
Specialized Supportive Care For Your Baby
Specialized supportive care for your baby may include:
Being placed in an incubator. Your baby will probably stay in an enclosed plastic bassinet (incubator) that's kept warm to help your baby maintain normal body temperature. Later on, NICU staff may show you a particular way to hold your baby — known as "kangaroo" care — with direct skin-to-skin contact.
Monitoring of your baby's vital signs. Sensors may be taped to your baby's body to monitor blood pressure, heart rate, breathing, and temperature. A ventilator may be used to help your baby breathe.
Having a feeding tube. At first, your baby may receive fluids and nutrients through an intravenous (IV) tube. Breast milk may be given later through a tube passed through your baby's nose and into his or her stomach (nasogastric, or NG, tube). When your baby is strong enough to suck, breastfeeding or bottle-feeding is often possible.
Replenishing fluids. Your baby needs a certain amount of fluids each day, depending on his or her age and medical conditions. The NICU team will closely monitor fluids, sodium and potassium levels to make sure that your baby's fluid levels stay on target. If fluids are needed, they'll be delivered through an IV line.
Spending time under bilirubin lights. To treat infant jaundice, your baby may be placed under a set of lights — known as bilirubin lights — for a period of time. The lights help your baby's system break down excess bilirubin, which builds up because the liver can't process it all. While under the bilirubin lights, your baby will wear a protective eye mask to rest more comfortably.
Receiving a blood transfusion. Your preterm baby may need a blood transfusion to raise blood volume — especially if your baby has had several blood samples drawn for various tests.
In the hospital, newborns are given a blood transfusion using neonatal picc catheters.
Medications for Premature Birth
Medications may be given to your baby to promote maturing and to stimulate the normal functioning of the lungs, heart, and circulation.
Depending on your baby's condition, medication may include:
- Surfactant, a medication used to treat respiratory distress syndrome
Fine-mist (aerosolized) or IV medication to strengthen breathing and heart rate
- Antibiotics if the infection is present or if there's a risk of possible infection
- Medicines that increase urine output (diuretics) to manage excess fluid
- An injection of medication into the eye to stop the growth of new blood vessels that could cause retinopathy of prematurity
- Medicine that helps close the heart defect known as patent ductus arteriosus
- Surgery. Sometimes surgery is necessary to treat a number of conditions associated with prematurity. Talk with your baby's health care team to understand which complications may require surgery, and learn about the type of surgery that might be necessary to treat them.
When it is the right Time to take your baby home after delivery?
Your baby is ready to go home when he or she:
- Can breathe without support
- Can maintain a stable body temperature
- Can breast- or bottle-feed
- Is gaining weight steadily
- Is free of infection
Medical References to Premature Birth
- Creasy RK, et al., eds. Preterm labor and birth. In: Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, Pa.; Saunders Elsevier: 2014. https://www.clinicalkey.com. Accessed Mar. 17, 2018.
- Boyle AK, et al. Preterm birth: Inflammation, fetal injury and treatment strategies. Journal of Reproductive Immunology. 2017;119:62.
- Cook WJ, et al. Mayo Clinic Guide to Your Baby's First Year. Intercourse, Penn.: Good Books; 2012:503.
- Kliegman RM, et al. The high-risk infant. In: Nelson Textbook of Pediatrics. 20th ed. Philadelphia, Pa.: Elsevier; 2016. clinicalkey website. Accessed Mar 17, 2018.
- Fenton TR, et al. A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants. BMC Pediatrics. 2013;13:59.
- Preterm labor and birth: An overview. National Institute of Child Health and Human Development. https://www.nichd.nih.gov/health/topics/preterm/Pages/default.aspx. Accessed Mar. 17, 2018.
- Gabbe SG, et al. Preterm labor and birth. In: Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, Pa.: Saunders Elsevier; 2017. https://www.clinicalkey.com. Accessed Mar. 17, 2018.
- Mayo Clinic. Disease conditions, premature birth. In: Diagnosis and treatment
- https://www.mayoclinic.org/diseases-conditions/premature-birth/diagnosis-treatment/drc-20376736. Accessed Mar. 17, 2018