What are some problems premature babies have?

premature baby with the mother

As a neonatologist, there are two questions I always hear from parents right after premature birth: 1. Will my child live? 2. What kind of problems will my baby have in the hospital and after discharge home?

In this article, I will give you an answer to the second question.

Every year, in the USA, over 350 thousand newborns are born as premature babies. Depending on race and other factors, the percentage of premature births ranges between 9% for healthy white mothers and 14% for African American women. Prematurity is defined as a birth before 37 weeks of gestational age, which is three weeks earlier than the assigned due date for delivery at 40 weeks (Source).

Depending on the degree of prematurity, babies will have no medical problems, mild medical issues, or severe health complications. Let’s list most of those medical problems and put them in one of the two groups: immediate-after birth and long-term issues after discharge home.

If you have a premature baby born before 32 weeks receiving treatment in the NICU right now, I encourage you to explore also my book “Babies Born Early

What are the problems associated with prematurity soon after birth?

  • Small birth weight
  • Temperature regulation issues
  • Feeding problems
  • Metabolic abnormalities: glucose, calcium
  • Jaundice (Hyperbilirubinemia)
  • Breathing problems (RDS)
  • Chronic breathing problems (BPD)
  • infections
  • Anemia
  • Necrotizing Enterocolitis – NEC
  • Retinopathy of Prematurity – ROP
  • Intraventricular Hemorrhage – IVH and other brain abnormalities
  • Heart problems: low blood pressure and Patent Ductus Arteriosus (PDA)

Long-term health issues associated with prematurity:

  • Movement disorders
  • Learning difficulties
  • Hearing problems
  • Vision acuity problems
  • Dental problems
  • Psychosocial problems
  • Chronic health issues related to feeding problems or chronic lung disease

Some rare conditions may be missing from those two lists. I also want to emphasize that your premature baby may only have some or even none of these conditions. Each patient is different, and types of complications will depend on numerous factors. Let me explain each of these conditions one by one.

Immediate health problems during NICU stay after birth:

The small size of the baby

Premature babies are born with decreased birth weight and short stature. Obviously, this is because they did not have enough time in utero to grow and gain enough weight. The average birth weight of the full-term baby in developed countries is 3.3 kg, at 35 weeks is 2.4 kg, at 32 weeks is 1.65 kg, at 28 weeks is 1 kg, and at 24 weeks is about 0.55 kg. 

The younger gestational age, the smaller birth weight will be. Smaller babies have less strength to breathe and to eat. The size is an essential factor contributing to their sickness and recovery. 

Temperature regulation issues

Premature babies tend to have problems with temperature regulation due to excessive heat loss and immature ability to regulate their temperature. Due to their size, the increased water content in their body, decreased fat content and decreased amount of energy resources, they are very prone to developing hypothermia.  

Doctors can prevent or treat hypothermia by using unique heated beds. They are called: radiant warmers and incubators – isolettes. 

Feeding problems

Some babies born at less than 35 weeks of gestational age and probably all babies born at less than 32 weeks will not know how to eat by mouth. If placed on the breast or offered a bottle with milk, they would not be able to suck, drink, and swallow. 

Essential skills such as suck, swallow, and coordination with breathing, so the baby does not aspirate milk into its lungs starts developing around 32 weeks and may not be mature until the baby is 37-40 weeks. While babies are learning how to eat by mouth, they can receive all their nutrition with IV fluids or with milk administered directly into their stomachs using special feeding tubes (Source). 

I often tell parents that for babies born after 28 weeks of gestational age, the most critical factors that will decide when their baby will be able to go home are: temperature regulation and the ability to eat well. For more premature babies, discharge predictions may be more challenging as they tend to have more complex health problems during their stay in NICU. 

Metabolic abnormalities

Many babies have metabolic abnormalities after premature birth. Most commonly, babies will have low glucose levels and low calcium. Glucose is a vital fuel for our brain, heart, and kidneys, while calcium is needed for the proper function of our bones, nerves, and muscles. 

We can supply both chemicals in IV fluids to babies to correct their levels. Some babies need IV fluids for weeks or even several months, particularly if they don’t tolerate appropriate feeding volumes. 

Jaundice – Hyperbilirubinemia of Prematurity

Many premature babies develop yellow skin due to elevated levels of bilirubin in their bodies. I wrote several articles on the topic of jaundice and phototherapy. Here, I want to emphasize factors that make premature babies more prone to earlier and prolonged hyperbilirubinemia: 

  • no feedings or delayed feedings
  • immaturity of liver enzymes
  • dehydration
  • delayed passage of stools
  • trauma during delivery

Jaundice in premature babies is treated the same way as in full-term babies by using phototherapy. Please see my article on phototherapy here. An important caveat regarding the treatment of preemies for jaundice is that bilirubin levels at which we start phototherapy are much lower than those for full-term babies. 

Breathing problems

Many babies who are born before 32 weeks of gestational age and most babies born below 28 weeks of gestational age will have respiratory distress syndrome. Respiratory distress syndrome is a condition that develops in babies due to anatomical and chemical immaturity of their lungs. The main culprit is deficiency or malfunction of the surfactant. However, an insufficient number of airways and gas exchange units such as pulmonary alveoli, play a significant role in the development of this disease as well. 

Babies that are affected by RDS (Respiratory Distress Syndrome) require supplemental oxygen for breathing and support of their respiratory efforts with different machines (Nasal Cannulas, CPAP device, or Ventilators). Some babies recover quickly, but in some babies, Respiratory Distress Syndrome evolves into a more chronic condition called BPD (Bronchopulmonary Dysplasia) or chronic lung disease. You can read more about RDS in my article here

BPD – Bronchopulmonary Dysplasia or Chronic Lung Disease

In some premature babies, Respiratory Distress Syndrome evolves slowly into another condition: BPD, also called chronic lung disease. BPD occurs mostly in babies who were born at less than 28 weeks. It is not clear why some babies develop this condition, and some do not. Probably infections and inflammatory factors may contribute to its development. 

There is no single diagnostic test for BPD. We make that diagnosis when a premature baby has persistent respiratory symptoms (fast breathing rate, increased work of breathing, abnormal blood gases) and requires additional oxygen to maintain normal oxygenation levels beyond 36 weeks of corrected age. 

Some babies with BPD just need more time to grow and overcome the disease. Others are very sick and need to be on a ventilator for a long time and must be treated with steroid medications. 


Pregnant women pass the majority of all immunoglobulins or antibodies needed by the baby during the third trimester. Therefore, babies born prematurely do not get that benefit. Maternal infections can be a cause of premature birth and lead to a baby catching that infection at birth as well. Finally, exposing a baby to different procedures and pieces of equipment during its NICU stay increases the chances of the infectious disease in a baby. 

As a result, premature babies are frequently tested for infections during their initial hospitalization and often treated with prolonged courses of antibiotics. 


Bone marrow in premature babies may not be able to keep up with blood losses due to many blood drawings necessary in NICU, resulting in anemia requiring blood transfusions. Extremely premature babies, those born at less than 28 weeks, frequently receive more than one transfusion during their stay in NICU. 

Necrotizing Enterocolitis – NEC

Necrotizing Enterocolitis (NEC) is an inflammatory condition of the baby’s bowel loops that affects 5%-10% of babies born at less than 30 weeks of GA or with a birth weight of less than 1250 gm. If affected, the baby develops severe feeding intolerance, abdominal distension, infections, bowel wall necrosis, and sometimes bowel perforation ending with death. 

It is a severe complication for premature babies resulting in many days being on IV fluids, antibiotics, and not being able to receive any feedings. Some babies require surgery to repair their perforated bowel loops and to treat peritonitis (peritonitis = severe infection of the abdominal cavity). Unfortunately, some babies may develop long term complications of NEC, such as absorption problems, and some may not even survive that diagnosis.  

Retinopathy of Prematurity – ROP

In newborns born before 32 weeks of gestational age, vasculature (blood vessels) in the eyes is not yet fully developed. For the reasons that we still do not understand, when blood vessels mature in the very sick premature babies, sometimes they enter the phase of a very abnormal growth that may lead to detachment of the retina and ultimately cause blindness in those babies. 

The condition is called Retinopathy of Prematurity or ROP. We suspect that factors that contribute to ROP are: the degree of prematurity, infections, the overall severity of the baby’s condition, fluctuations in oxygenation levels, glucose levels and others. 

We can monitor a baby for the development of the ROP and intervene if the disease is advanced enough to warrant treatment. We do not know how to prevent that disease from occurring. Most NICUs will monitor very premature babies starting from 4-5 weeks after birth until their eyes become fully mature. 

When a baby requires treatment, there are two options: laser surgery or injectable medication that can be given directly into the eye. Each of these techniques has its advantages and disadvantages. Unfortunately, despite the treatment, some babies with ROP end up with unfavorable visual outcomes. (My full article about ROP). 

Intraventricular Hemorrhage – IVH

Blood vessels in very premature babies are very fragile, and in very sick babies may rupture, leading to intraventricular hemorrhages. Ventricles are the spaces within our brain where cerebrospinal fluid floats. In a rare situation, very premature babies may develop bleeding in those spaces (intraventricular hemorrhage). 

In milder cases, blood from the ventricles may get absorbed, and everything heals without any sequelae. However, sometimes bleeding may be extensive and severe. Blood clots may lead to obstruction of the flow of cerebrospinal fluid resulting in hydrocephalus. 

Babies who were diagnosed with severe intraventricular bleeds and hydrocephalus are at higher risk to have neurodevelopmental impairment later in life. All of them should be referred to early intervention programs. 

Heart Problems

The extremely premature babies and micro preemies often have a problem with maintaining appropriate blood pressure levels and may suffer from PDA. PDA stands for Persistent Ductus Arteriosus. PDA is a connection that exists in a fetus. It allows for the flow between the pulmonary artery and aorta, the two largest arteries that are coming out of the heart. After birth, PDA is supposed to get closed on its own. However, that sometimes does not happen in premature babies and leads to numerous problems. 

Persistently open Ductus Arteriosus may be a cause of low blood pressure, cardiac failure and may worsen lung function in a baby. In some severe cases, PDA needs to be treated with medications or even surgery. 

Long-term issues associated with prematurity:

Unfortunately, health problems do not end for premature babies at the time of discharge from the NICU. Many babies suffer long term consequences of being born prematurely. Some health problems during childhood may be directly linked to the complications the baby suffered from during NICU stay (ROP, NEC), and others may only be associated loosely with prematurity (asthma, social problems). Frequency and severity of long term health problems are usually proportional to the degree of prematurity; extremely premature babies and micro-preemies are affected the most.

Movement disorders

Some premature babies develop motor problems during their childhood. Motor problems encompass a broad spectrum of conditions such as cerebral palsy, muscle tone issues, not being able to walk, eat, etc. 

Motor problems may be due to some identifiable events such as intraventricular hemorrhage or hydrocephalus, but sometimes it is difficult to find any reason other than prematurity. 

Learning difficulties

Some premature babies, especially those born very early, may have learning difficulties and will require special education services at school. Also, some ex-premature babies may have sensory problems such as impaired vision or hearing that will be contributing to their school problems. 

Dental problems

Delayed tooth eruption, discoloration of the teeth, and malalignment are conditions described to more frequently occurring in former premature babies. 

Psychosocial problems

Some researchers point out that premature babies are more likely to have behavioral and psychosocial problems. In my opinion, the exact extent to which this risk is increased among premature babies still needs further study. 

Chronic health issues related to feeding problems or chronic lung disease

If a premature baby suffered from NEC during its NICU stay, he or she might have long term bowel motility problems or malabsorption syndrome. Malabsorption syndrome occurs in patients who have undergone surgery for bowel perforation, and the surgeon had to remove a significant portion of the baby’s bowels. That can result in not having enough intestines to digest and absorb an adequate amount of food for growth.

Children who suffered from chronic lung disease and had numerous bouts of pneumonia and stayed on ventilators for a long time may be more prone to asthma and frequent respiratory infections in the future. 

If you are a parent of premature baby staying in the NICU right now, you may want to read my article: What to do after giving birth to a premature baby?

You can also find many more of my articles if you search for them under category “Preemie Babies” on the top of this page or go to my Home Page: NeoPedEdu.com.


This article is only for general information purposes. It should not be viewed as any medical advice. There is a chance that information here may be inaccurate. It would be best if you always discussed all health-related matters with your doctor before making any decisions that may affect your health or health of your family members.


Dr.Wisniewski is a board-certified pediatrician and neonatologist with over 20 years of clinical experience in the USA. He authored the book: "Babies Born Early - A guide for Parents of Babies Born Before 32 Weeks" Dr.Wisniewski loves educating parents on various health conditions affecting their newborn babies and children.

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