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Preterm Birth


Preterm birth or a premature birth refers to a birth of a baby who is born before 37 weeks of gestation. The normal duration of pregnancy is 37-40 weeks. The baby passes through several stages of development throughout the pregnancy, especially the maturation of organs already formed at the end of pregnancy. For instance, the lungs, the brain, and liver fully develop in the final weeks of pregnancy. So the babies born before that time will face difficulties in using these organs in their immature forms, which is responsible for the emergence of most health problems.  The infants suffer from these problems, and the mother and family face a lot of psychological and financial struggles due to preterm birth. The difficulties are more if the baby is born earlier than 32 weeks, causing increased disability and death rates. Almost 17% of infant deaths are due to preterm birth and low birth weight. Babies who are lucky enough to survive will face health problems like breathing difficulties due to immature lungs, feeding problems, cerebral palsy, vision and hearing problems, developmental delay, etc. such infants need special care just after birth to help them survive this critical period. 


Preterm babies are classified according to the week they are born. The earlier they are born, the more immature they are, the higher the complications.

  • Late preterm: Babies born between 34 and 36 weeks of gestation (pregnancy) are termed late preterm. Most of the preterm births are of this type.
  • Moderately preterm: Babies born between 32 and 34 weeks of gestation (pregnancy) are termed late preterm.
  • Very preterm: Babies born before 32 weeks of gestation (pregnancy) are termed very preterm.
  • Extremely preterm: Babies born at or before 25 weeks of gestation (pregnancy) are extremely preterm.


Pregnancy and childbirth are extremely intricate and complex procedures. During pregnancy, a woman’s body undergoes several physiological changes to support the growth and development of the baby. Similarly, the baby made by fusion of just an egg and sperm goes through tremendous developmental processes before becoming a full-term baby. The placenta that attaches a baby to the mother's womb also provides nutrients for the developing baby and removes the waste materials to be excreted by the mother's body. It supplies the chemicals and hormones to the growing baby and protects them from infections by providing immunoglobulins (immunity). When the baby is born before time, his organs, which were previously dependent on the placenta, are too immature to handle the challenges outside the mother’s womb ad have their functional limitations.

Preterm births can occur spontaneously, or anything that can negatively affect a pregnancy's meticulous process can result in preterm birth. Some of these factors are;

  • If the mother has some chronic illnesses like diabetes, hypertension, infections
  • Developing high blood pressure during pregnancy (preeclampsia)
  • Maternal use of recreational drugs or alcohol or tobacco
  • Having more than one baby in the womb (twins or triplets)
  • Some problems with the uterus or cervix
  • Very less time between the two pregnancies
  • Developing vaginal infections or bleeding during pregnancy

Risk Factors

Some of the traits can put you at higher risk of preterm labor and preterm birth;

  • Family history of preterm births
  • Have a personal history of preterm births
  • If you are less than 20 years or more than 40 years of age
  • If you are an African American
  • Being underweight or overweight
  • If you smoke during pregnancy


Around 15 million babies are born prematurely every year worldwide. About 12% of the infants in the USA are born prematurely. Preterm births occur more commonly in low socioeconomic groups, teenage girls, or women over 40 years of age. 

Signs And Symptoms

Babies born prematurely are susceptible to developing the following health conditions;

1. Problems related to lungs:

  • Surfactant (a special substance in the lungs) is made by the cells that develop in the later weeks of pregnancy. An insufficient quantity of surfactant causes breathing difficulties.
  • Premature infants can face chronic lung damage due to bronchopulmonary dysplasia, which is the underdevelopment of the lungs.
  • They can also develop apnea of prematurity, i.e., they have breathing pauses.

2. Problems related to the brain: Preterm infants have an increased risk of bleeding in the brain called intraventricular bleeding

3. Problems related to the gut: A preterm baby's immature and delicate intestines can develop a severe inflammation called necrotizing enterocolitis.

4. Problems with the heart: There are more chances of developing heart defects like patent ductus arteriosus and inefficient blood pressure control leading to hypotension.

5. Neonatal sepsis: Due to a weak immune system, they can develop serious infections leading to sepsis.

6. Temperature control: They may also have problems maintaining temperature due to less body fat.

Developmental problems

  • Cerebral palsy: It is a disorder of movement and posture because of brain injury.
  • Vision and hearing problems: They face hearing and vision difficulties due to immaturity. One special entity is retinopathy of prematurity which is a problem in the retina.
  • Learning disabilities: they may achieve the milestones later than their full-term counterparts and face problems with learning challenges.
  • Poor growth: These babies may have difficulties feeding and have poor growth. They may also suffer from some psychological and behavioral problems.


When a baby is born prematurely, he must be kept in close supervision and monitoring to prevent complications. The following laboratory test should be performed to diagnose the problem and correct it immediately.

  • Blood glucose measurement: Blood glucose should be checked frequently as premature infants are prone to develop hypoglycemia.
  • Complete blood count (CBC): This test may show if the baby has anemia (low hemoglobin) or polycythemia (more than the normal amount of cells). It may also show increased or decreased levels of white blood cells, indicating infection.
  • Serum electrolytes: These are very important to determine as infants can frequently get low or high levels that should be maintained within normal limits.
  • Fluids monitoring: urine output should be measured to check for dehydration.
  • Imaging studies: An X-ray of the chest can show problems with the lungs and heart.

Differential Diagnosis

Two of the other disorders look like a preterm birth;

  • Extremely Low Birth Weight Infant
  • Fetal Growth Restriction


Preterm babies are admitted to special neonatal units, where they are monitored closely. Many babies need only supportive care, while some may need antibiotics for infections.

  • Incubator care: Your baby may need to be kept in enclosed units to maintain temperature and keep him safe from external hazards.
  • Vital signs: Temperature, heart rate, blood pressure are very important and need to be measured frequently.
  • Glucose: Your baby’s blood glucose levels would be checked frequently and corrected when needed.
  • Bodyweight: Daily gain in body weight would be checked.
  • Input-output: The amount of fluids administered and urinary output would be checked to prevent dehydration. Similarly, electrolytes would be checked for.
  • Feeding tube: Your baby may need a feeding tube inserted through the nose up to the stomach in the initial days for feeding milk.
  • Light therapy: Due to the development of jaundice, your baby may be placed under special UV lights.


Your baby may need the following medicines:

  • Surfactant: It is a medication used to treat respiratory distress syndrome.
  • Antibiotics will be given to treat an infection or prevent developing an infection if present.
  • To close the heart defect PDA, a medicine, may need to be given. For example, NSAIDs- ibuprofen and indomethacin.
  • A special injection (Intravitreal Ranibizumab) may need to be given into the eye to prevent eye complications.

Some complications may need some surgical procedures as decided by the doctors considering the requirements of the baby. 


Preterm birth has to be handled carefully and vigilantly. Carelessness can result in severe consequences, even death. It has been the leading cause of mortality in neonates resulting in around 70% of neonatal deaths. Mortality is higher in developing countries. The most common complications are infections, respiratory failure, and congenital malformations. Infants who receive corticosteroids during the 24-34 weeks have better respiratory outcomes.


Some of the risks of getting a premature birth can be prevented by adopting the following habits.

  • Diet improvement: A person is advised to take a healthy balanced diet that must have vitamins, minerals, amino acids, antioxidants, etc.
  • Stress management: Exercises and therapies to manage stress must be done.
  • Exercises: A person is advised to perform some sort of regular exercise.
  • Adequate sleep and rest: You must maintain good sleep hygiene and take enough rest. 
  • Stay alcohol and tobacco-free: Do not drink alcohol or smoke tobacco while pregnant.
  • Prenatal care: Be very punctual and vigilant regarding your antenatal follow-ups.
  • Pregnancy gap: Maintain a good gap between two pregnancies, at least 18 months.
  • Medicines: Avoid taking any medication without your doctor's advice. Never take any illicit drug while pregnant.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 27, 2023.


Preterm birth (

Global burden of preterm birth - Walani - 2020 - International Journal of Gynecology & Obstetrics - Wiley Online Library

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