Micro Preemie: Survival Rates, Risks And Complications

check_icon Research-backed

Image: Shutterstock


A micro-preemie is a baby born before 28 weeks of gestation with less than 1000 grams of body weight (1). It is common for micro-preemies to develop complications due to their small size and low birth weight. Hence, they usually require continuous monitoring and care in the neonatal intensive care unit (NICU) after birth. Usually, doctors may recommend that the baby be admitted to the hospital until they can survive outside without support.

Doctors usually try to sustain pregnancy and delay premature delivery whenever possible since the fetus is still developing and has an immature immune system and underdeveloped lungs compared to a term baby. Thus, micro-preemies may receive certain medications to promote lung maturity and function. Although most micro-preemies grow to term babies, some may have health complications.

Read on to know more about causes, short-term and long-term risks, complications, and management of micro-preemies.

Causes Of Micro-Preemie 

There could be many reasons for premature delivery, and most of them happen spontaneously. According to the World Health Organization (WHO), some of the common causes of preterm births include:

  • Multiple pregnancies
  • Infections
  • Gestational diabetes
  • Preeclampsia
  • Genetics
  • Previous premature deliveries (2)

If you have any of the above conditions, keep in touch with your doctor to avoid premature delivery.

Sometimes preterm deliveries are induced especially when the baby has reached late preterm age for maternal or obstetrician convenience or to get an auspicious birth date. Such practices should be strongly discouraged.

As micro-preemies are at a higher risk of developing complications, their survival rate is also critical (3).

What Are The Devices Connected To A Micro-Preemie? 

Seeing a micro-preemie inside the NICU may not be a pretty sight. Their body will be tiny, with visible veins. You will also find the below equipment attached to support various functions of their body.

  • Respiratory support 

As their lungs are underdeveloped, micro-preemies need external ventilation support to help them breathe. A number of devices are used in the NICU to provide respiratory support like nasal cannula, oxygen hood, ventilators etc. Sometimes endotracheal tubes (ET tubes) work as an interface between the baby and the ventilator and help them breathe. These tubes pass through the vocal cords and come out of their mouth. If the baby can breathe independently, then lesser invasive methods, such as the continuous positive airway pressure (CPAP), where a mask is strapped to the baby’s mouth, are used (4).

  • NG/OG Tube 

Micro-preemies generally do not suck efficiently and lack coordination between sucking, swallowing, and breathing (5), so they are fed using external feeding tubes, such as a nasogastric tube (NG) or orogastric (OG) tube. These tubes go from their mouth into the stomach.

  • Intravenous lines 

Micro-preemies also need continuous IV fluids over a long period as their bodies are not yet ready to absorb nutrients. IV access is also needed for administration of many life-saving medicines, including antibiotics, drugs for maintaining circulation and respiration and blood and blood products.

A percutaneously inserted central catheter (PICC) ensures a constant flow of IV fluids and minimizes the need for repeated punctures. Simple peripheral IV catheters need changing usually every 2 or 3 days while PICC lines can last 2-6 weeks. The PICC is inserted into a small vein on the leg or arm and then moved into a larger vein (6).

  • Phototherapy 

Jaundice is a common complication in micro-preemies. Phototherapy is used to treat neonatal jaundice. In this therapy, the baby is placed under lamps emitting 400–500 nanometers wavelength light (7).

  • Monitoring devices 

Micro-preemies need to be continuously monitored to understand if their body is getting better and e adapting to independent survival. Many devices are connected to the incubator and your baby, which constantly monitor them and send data. The incubators also have alarm systems in place to alert any abnormalities. Some of the monitoring devices used include cardiorespiratory monitor, blood pressure monitor, temperature monitor, pulse oximeter, transcutaneous oxygen, and carbon dioxide monitor (8).

Next, we tell you about the various risks and complications micro-preemies face. For easy understanding, we have grouped these into long-term and short-term risks and complications.

Possible Short-Term Health Risks And Complications For Micro-Preemies

Certain short-term health issues in micro-preemies are seen immediately after birth or during their stay in the NICU. The doctors carefully monitor them to try and resolve these issues if and as soon as they arise.

1. Patent ductus arteriosus (PDA) 

In a developing infant, the pulmonary artery and the aortic arch are connected by a vascular shunt called ductus arteriosus. It diverts the blood from the right ventricle and prevents it from entering the lungs. The shunted blood doesn’t get oxygenated as it bypasses the lungs. This is normal in a fetus as a fetus receives oxygenated blood through the placenta and umbilical vein. Once the baby is delivered it loses connection with the placenta and blood needs to be oxygenated in the lungs for survival.

In full-term infants, this shunt closes within a few hours of birth, whereas in micro-preemies, this process is delayed and defective oxygenation of blood can lead to:

Treatment: Medical therapy with cyclo-oxygenase inhibitors, such as indomethacin and ibuprofen, is the mainstay treatment option for PDA. Surgical interventions are also done for babies who do not respond to medical treatment (9).

2. Respiratory distress syndrome (RDS) 

Although all babies born before 37th week of pregnancy are at risk of developing respiratory distress syndrome, it occurs very often with varying degrees of severity in those born before 28th week. It is a breathing difficulty caused due to insufficient surfactant in the lungs, causing the alveoli to collapse.

  • Breathing problems
  • Cyanosis (blue coloration of the skin)
  • Flaring nostrils
  • Pulling in of ribs and breast bones while breathing
  • Grunting sounds while breathing

The symptoms usually occur immediately after birth, worsen by the second or third day, and get better with treatment.

Treatment: Oxygen supplementation is the mainstay of treatment. Breathing support is often required by micro-preemies which is provided by continuous positive airway pressure device or mechanical ventilator. Surfactant replacement therapy may also be needed (10).

3. Neonatal sepsis 

Newborns in general have an immature immune system, making them susceptible to infections that could lead to neonatal sepsis. Micro preemies are especially vulnerable. Infections may be transmitted before, during or after birth from the mother or from the surroundings. Again these babies usually have to undergo multiple procedures in order to survive ranging from tube feeding to ventilatory support which can lead to infections despite all precautions being taken. .. Neonatal sepsis is characterized by:

  • Fever
  • Vomiting
  • Diarrhea
  • Cyanosis
  • Tachycardia
  • Hypotension
  • Seizures
  • High-pitched cry
  • Jaundice

Sepsis is classified into early-onset (that occurs from birth to three days) and late-onset (occurring after the third day of life) due to specific causes and management associated with each type.

Treatment: Neonatal sepsis should be identified and treated as it leads to significant morbidity and may cause mortality. The treatment includes antibiotic therapy and supportive care to deal with the complications of infection (11).

4. Retinopathy of prematurity (ROP) 

Retinopathy of prematurity is an eye disorder caused by abnormal blood vessel growth in the retina of premature infants. It may affect any newborn born before 34 weeks and weighing less than 2kg. Generally, lower the gestational age and birth weight higher is the risk of developing ROP. ROP is classified into five stages, ranging from mild to severe. Advanced ROP may cause vision loss. There are no early symptoms of ROP, but late symptoms include:

  • Unusual movement of the eyes
  • White pupils
  • Vision loss

Treatment: Based on the stage, regular monitoring, surgical intervention, such as laser therapy or cryotherapy, is recommended. Anti-vascular endothelial growth factor injection is a newer promising modality of treatment (12).

5. Intraventricular hemorrhage (IVH)

It is a condition in which the blood vessels within the brain rupture and disrupt the cerebral blood flow. IVH usually occurs between three to seven days of birth and can be detected through ultrasound scans of the head. For this reason, routine ultrasound screening is done in micro preemies at regular intervals and on suspicion. It is a major complication in micro-preemies with potential to adversely affect their survival and neurological development.

It may be asymptomatic or associated with symptoms like:

  • Breathing difficulties
  • Decreased muscle tone
  • Changes in heart rate and blood pressure
  • Lethargy and excessive sleep
  • Seizures

Treatment: Although there is no way to stop the bleeding, the NICU team will try to keep the situation stable by treating the complications and, if needed, a spinal tap to drain the excess fluid to relieve the pressure on the brain. Micro-preemies with this condition are closely monitored and need to be on regular follow up even after discharge from the NICU.. .

The chances of this complication can be reduced by giving the mother corticosteroids before birth as recommended by doctors (13).

6. Necrotizing enterocolitis (NEC)

This is a common intestinal inflammatory disease found in micro-preemies. As the digestive system of premature babies is underdeveloped, it is susceptible to infections and injuries. In NEC, the lining of the intestine gets inflamed and begins to die. Sometimes, it may be difficult to diagnose as the symptoms are similar to those occurring in other complications. Some common symptoms include:

  • Body temperature fluctuations
  • Lethargy
  • Breathing difficulties
  • Swollen abdomen
  • Blood in stools

This complication occurs in three stages, wherein the last stage comprises deterioration of vital signs, gastrointestinal bleeding, and septic shock.

Treatment: It is important to identify NEC early on to help prevent its devastating effects. Treatment options include gastric decompression and antibiotic treatment. Surgical intervention may be recommended if the condition does not respond to medications (14) (15)

These are some short-term risks and complications that might occur in a micro-preemie. The doctors carefully monitor the baby and treat these conditions in the NICU. A micro-preemie may have to stay for months in the hospital. However, this period might extend or reduce based on the progress made by the baby.

A micro-preemie may also have some long-term health issues that might show up once they are sent home. So, it is important to monitor your baby carefully and take them for regular consultations. However, these complications may not occur in all micro-preemies. Read the next section to understand some long-term complications and risks of micro-preemie.

Long-Term Complications Of Micro-Preemie

 Micro-preemies are at risk of developing long-term complications that may continue into adulthood. However, this may not be the case for all micro-preemies because some babies would meet milestones and develop normally after getting discharged from the NICU. It is important to understand the various issues faced by micro-preemies.

1. Developmental delays 

Most premature babies go on to develop like their full-term peers. But the earlier they are born, the more likely it is that they’ll have development problems. However positive parenting plays a big role in helping these children catch up usually around the age of two to three years.

Some commonly affected domains are fine motor skills (eg. holding a pencil), visuomotor coordination and language (16).

2. Cerebral palsy 

Prematurity is a major risk for CP and the risk is especially high for babies born before 32 weeks (17). Cerebral palsy consists of a group of disorders that affect body movement, posture, and balance.

3. Digestive issues

Digestive issues such as constipation, colic, and gastroesophageal reflux are found more in micro-preemies than full-term babies. It could be because premature babies are bottle-fed, and they have poor muscle tone and immature gut function. If your child shows signs of digestive issues, consult your pediatrician (18).

4. Chronic lung disease 

Lungs are one of the last organs to form in a baby. This is why most micro-preemies have underdeveloped lungs at the time of birth. A premature baby might need a ventilator to assist its breathing. Sometimes, assisted ventilation might damage the baby’s fragile lungs, causing chronic lung disease. It is characterized by flaring nostrils, fast breathing, grunting, and chest retractions (19).

5. Auditory issues

Studies state that one to three in 1000 newborns have hearing loss while as many as 15 out of 100 (not 1000) preemies may have significant hearing loss (20).

Micro-preemies face many complications, so doctors always try to avoid preterm delivery. The World Health Organization (WHO) has issued the below guidelines to improve preterm birth outcomes.

  • Use of corticosteroids before birth to accelerate the development of the lungs
  • Use of antibiotics before the breakage of water and the onset of the labor
  • Administration of magnesium sulfate to prevent future neurological impairments (2)

How Can You Help A Micro-Preemie To Have A Better Outcome? 

You can do a few things to help a micro-preemie have a better outcome and improve their survival chances.

  • If you suspect a premature birth, look for a hospital with a level III NICU and 24-hour neonatology coverage.
  • Identification of the common signs of preterm labor would also help you and the baby get timely medical care. Some signs include regular contractions before the term, cervical changes, pelvic pressure, menstrual-like cramps, watery vaginal discharge, and lower back pain (21).
  • Seeking early interventions that involve supporting parents to improve the infant’s environment and educating the parents in caring for preterm infants can positively reduce the risk of neurodevelopmental disabilities (22).

How To Take Care Of A Micro-Preemie While In The NICU?

It can be quite stressful for the parents when the baby is born preterm and in the NICU. It would be difficult for the parents to see the baby surrounded by monitors and machines. You would want to help the baby in whatever way possible. However, you need to be extremely careful while handling a micro-preemie. Here are a few ways in which you could help your micro-preemie while they are in the NICU.

  • Ask the NICU nurse or your doctor if it is ok to hold your baby. Even if you cannot hold them, you can always touch them. Be with them or even sing to them.
  • You can breastfeed or bottle-feed your baby as soon they are old enough to feed without the feeding tubes. If your baby is still on feeding tubes, pump the breast milk, and feed them.
  • Skin-to-skin contact, also called kangaroo care, is a method that has many advantages for the mother and the premature baby. It helps stabilize the infant’s heart rate and temperature, decrease arousal and REM sleep, promote a better sleep-wake cycle, assist in successful breastfeeding, etc. If your doctor has given you a green signal for kangaroo care, do administer it regularly (23).
  • If you are required to leave the NICU, trust that your baby is in good hands and use this time to prepare yourself and the family for the baby’s arrival.
  • Don’t hesitate to ask questions. Ask all your queries before taking discharge. When the doctor gives you the discharged date, spend as much time as possible with the baby and take care of all the needs like feeding, massaging, changing etc., so that you get the hang of things before taking the baby home.

Having a premature delivery and a micro-preemie in NICU can take a toll on the parents. We agree it is not easy to deal with such a situation. However, the physical and mental health of the parents is equally important. Here are a few things you could do:

  • Talk to your doctor and discuss with them about your baby’s progress.
  • Do not neglect your own needs; do something relaxing, such as reading a book or going for a walk.
  • Turn to family and friends for support. Reach out to them and share your feelings with them.
  • If you are still feeling stressed, talk to a therapist for support and guidance.
  • Read success stories of micro-preemies or talk to other parents who have gone through the same situation.

A micro-preemie might face many health complications during and after birth, so it is important to understand the health issues and how you can help your baby. While this whole situation can be extremely stressful, it is equally rewarding to see your little fighter defy all odds and grow into a healthy and happy baby.

Frequently Asked Questions

1. Is there any difference between a premature baby and a micro-preemie?

Babies are distinguished as extremely premature (micro preemie, born before 28 weeks of gestation), very premature (born in 28–31 weeks), and moderately premature (32–36 weeks) based on the degree of prematurity during birth (24).

2. When can micro preemies wear clothes?

Micro preemies might wear clothing only after being discharged from the NICU (varies broadly among babies, depending on their growth and overall health status). Nevertheless, if your doctor gives the go-ahead, ensure that you avoid fluffy materials and high necklines (25).

Key Pointers

  • A baby born before 28 weeks of gestational age weighing less than 1000 grams is called a micro-preemie.
  • Infections, gestational diabetes, multiple pregnancies, etc., are some causes of preterm births.
  • Preemies may need respiratory support, NG/OG tube, intravenous lines, etc., for some weeks to support their body functions.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. A Micro-preemie Grows Up and Gives Back; Stanford Children’s Health
2. Preterm birth; World Health Organization
3. T H H G Koh, H Harrison, and A Casey; Prediction of survival for preterm births; The British Medical Journal (2000).
4. Breathing support for premature babies; Tommy’s
5. Nasogastric Versus Orogastric Route of Feeding in Preterm; ClinicalTrails.gov
6. Percutaneously inserted central catheter – infants; Medline Plus
7. Phototherapy; Sydney Local Health District
8. A Survey on Neonatal Incubator Monitoring System; Journal of Physics: Conference Series
9. Olachi J. Mezu-Ndubuisi, et al.; Patent Ductus Arteriosus in Premature Neonates; HHS Author Manuscript (2012).
10. Respiratory Distress Syndrome (RDS) in Premature Babies; Stanford Children’s Health
11. Chandan Kumar Shaha, et al.; Neonatal sepsis – a review; Bangladesh J Child Health (2012).
12. Retinopathy of Prematurity; National Eye Institute
13. Intraventricular hemorrhage of the newborn; MedlinePlus
14. Katherine E. Gregory, et al.’ Necrotizing Enterocolitis in the Premature Infant; HHS Author Manuscript (2011).
15. Mashriq Alganabi, et al.; Recent advances in understanding necrotizing enterocolitis; F1000Research (2019).
16. Norbert Zmyj, et al.; Social Cognition in Children Born Preterm: A Perspective on Future Research Directions; Frontiers in Psychology (2017).
17. Maria Hafström, et al.; Cerebral Palsy in Extremely Preterm Infants; Pediatrics- Official Journal of The American Academy of Pediatrics (2018).
18. Your premature baby’s digestion; Tommy’s
19. Chronic Lung Disease in Premature Babies; University of Rochester Medical Center
20. Jung Ho Han, MD, et al.; Hearing Impairments in Preterm Infants: Factors Associated with Discrepancies between Screening and Confirmatory Test Results; Neonatal Medicine (2020).
21. Vrishali Suman; Preterm Labor; Statpearls
22. Karen M Benzies, et al.; Key components of early intervention programs for preterm infants and their parents: a systematic review and meta-analysis; British Medical Journal (2013).
23. Ann L Jefferies; Kangaroo care for the preterm infant and family; Pediatric Child Health (2012).
24. Ewa Skrzetuska et al., Assessment of the Impact of Clothing Structures for Premature Babies on Biophysical Properties; Materials (2021).
25. Transitioning Newborns from NICU to Home; Agency for Healthcare Research and Quality.
Was this information helpful?
The following two tabs change content below.

Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more

Dr. Pooja Parikh

Dr. Pooja Parikh is a pediatrician whose medical journey has taken her from Rajkot (PDUMC) to Vadodara (SSGH) to Mumbai (Hinduja & Breachcandy Hospital). Currently she is actively involved in critical, intensive and general care of 0 to 18-year-olds in the port town of Gandhidham, where she was born and brought up. She believes that a doctor should be involved... more