What Are the Most Common Problems in the NICU?

Nearly 1 in 10 babies born in the United States requires care in the Neonatal Intensive Care Unit (NICU). That number has been climbing steadily in recent years, reaching 9.8% of all births as of 2023, up from 8.7% in 2016. For parents watching their newborn in an incubator surrounded by monitors and medical equipment, understanding what their baby is facing can feel overwhelming.

NICU admissions happen for many reasons: premature birth, complications during delivery, infections, birth defects, or breathing problems. While each baby’s situation is unique, certain medical conditions appear more frequently than others in the NICU. Knowing what these conditions are, why they happen, and how doctors treat them can help families navigate this difficult time with more confidence.

Why Are More Babies Requiring NICU Care?

The rise in NICU admissions reflects several trends. More babies are being born prematurely or with low birth weight, and advances in medical care now allow even extremely premature infants to survive when they would not have in the past. Additionally, improved monitoring during pregnancy and delivery means more babies with potential complications are identified and admitted to the NICU as a precaution.

Preterm infants (those born before 37 weeks) and babies with very low birth weight (less than 1,500 grams or about 3.3 pounds) face the highest risks and account for a significant portion of NICU admissions. Many of the most serious NICU complications stem directly from the challenges of being born too early, before organs have fully developed.

What Is Respiratory Distress Syndrome and Why Does It Happen?

Respiratory distress syndrome (RDS) is one of the most common reasons premature babies need intensive care. In RDS, a baby’s lungs lack sufficient surfactant, a slippery substance that keeps the tiny air sacs in the lungs from collapsing. Without enough surfactant, breathing becomes extremely difficult.

RDS occurs primarily in premature infants because surfactant production doesn’t reach adequate levels until late in pregnancy. Babies born before 34 weeks are at highest risk. Signs include rapid, labored breathing, grunting sounds, flaring nostrils, and a bluish tint to the skin from low oxygen levels.

Treatment typically involves:

• Surfactant replacement therapy delivered directly into the lungs
• Oxygen support through various methods depending on severity
• Continuous positive airway pressure (CPAP) to keep airways open
• Mechanical ventilation for more severe cases

With proper treatment, most babies recover from RDS, though very premature infants may develop chronic lung disease requiring longer-term respiratory support.

What Are Apnea and Bradycardia in Newborns?

Apnea means a baby stops breathing for more than 15 to 20 seconds. Bradycardia is when the heart rate drops significantly, usually below 80 beats per minute. In the NICU, these two conditions often occur together, particularly in premature babies.

Premature infants experience apnea and bradycardia because the part of the brain that controls breathing isn’t fully mature. The condition, called “apnea of prematurity,” is extremely common in babies born before 34 weeks and nearly universal in those born before 28 weeks.

These episodes can be frightening to witness. NICU monitors will alarm when they detect apnea or bradycardia, and nurses respond quickly. Often, gentle stimulation is enough to restart normal breathing and heart rate. Some babies need:

• Caffeine citrate medication to stimulate the respiratory center in the brain
• CPAP or other breathing support
• Monitoring until the episodes resolve, which usually happens as the baby matures

Most babies outgrow apnea of prematurity by the time they reach what would have been 36 to 37 weeks of pregnancy.

How Serious Is Neonatal Sepsis?

Neonatal sepsis is a life-threatening bloodstream infection that can quickly become critical. It’s one of the leading causes of death in newborns worldwide, particularly in the first week of life. Sepsis requires immediate antibiotic treatment because the infection can rapidly spread to multiple organ systems.

Two types of neonatal sepsis exist: early-onset (within 72 hours of birth) and late-onset (after 72 hours). Early-onset sepsis often comes from bacteria the baby encounters during delivery, particularly Group B Streptococcus and E. coli. Late-onset sepsis may result from bacteria in the NICU environment or medical procedures.

Signs of sepsis can be subtle or dramatic:

• Temperature instability (too high or too low)
• Difficulty breathing
• Poor feeding
• Lethargy or irritability
• Fast or slow heart rate
• Low blood sugar

Doctors start broad-spectrum antibiotics immediately when sepsis is suspected, often before test results confirm infection, because waiting can be fatal. Blood cultures determine the specific bacteria involved, allowing doctors to adjust antibiotics accordingly. Premature babies, those with low birth weight, and infants whose mothers had certain infections during pregnancy face higher sepsis risk.

What Is Necrotizing Enterocolitis and Who Gets It?

Necrotizing enterocolitis (NEC) is a devastating intestinal condition where portions of the bowel become inflamed and can die. It affects 5% to 10% of very low birth weight premature infants and carries a mortality rate as high as 30%. NEC is one of the most feared complications in the NICU.

The exact cause remains unclear, but NEC seems to result from an immature intestinal system that can’t properly handle feeding and defend against bacteria. It occurs almost exclusively in premature babies, with the smallest and youngest at greatest risk.

Warning signs include:

• Swollen, tender, or discolored abdomen
• Inability to tolerate feedings
• Bloody stools
• Decreased activity
• Breathing difficulties
• Temperature instability

Treatment depends on severity. Early cases may respond to stopping feedings, providing intravenous nutrition, and giving antibiotics. More advanced cases require surgery to remove dead bowel tissue. Babies who survive severe NEC may face long-term complications including short bowel syndrome, requiring specialized nutritional support for months or years.

What Causes Brain Bleeding in Premature Babies?

Intraventricular hemorrhage (IVH) is bleeding in or around the fluid-filled spaces (ventricles) inside the brain. It occurs in up to 15% of infants born before 32 weeks of pregnancy. The bleeding happens because fragile blood vessels in the developing brain rupture, often in the first few days after birth.

Several factors increase IVH risk:

• Extreme prematurity (especially under 28 weeks)
• Very low birth weight
• Respiratory distress requiring mechanical ventilation
• Unstable blood pressure
• Blood clotting problems
• Infection

IVH is graded from 1 to 4 based on severity. Grades 1 and 2 are mild, with bleeding confined to small areas, and often resolve without causing permanent damage. Grades 3 and 4 involve more extensive bleeding that can damage brain tissue and lead to serious complications.

Doctors diagnose IVH through ultrasound imaging of the brain, typically screening all babies born before 30 weeks. There’s no way to stop bleeding once it starts, so treatment focuses on managing complications. The most serious concern is hydrocephalus, where fluid builds up in the brain, sometimes requiring a shunt.

About 25% of babies with severe IVH develop significant neurodevelopmental problems, including cerebral palsy, intellectual disability, seizures, and learning difficulties. Close monitoring and early intervention services improve outcomes for affected children.

What Is Hypoxic-Ischemic Encephalopathy?

Hypoxic-ischemic encephalopathy (HIE) is brain damage caused by oxygen deprivation and reduced blood flow to the brain around the time of birth. It’s one of the most serious birth complications, affecting approximately 1 to 2 per 1,000 full-term births. HIE can result from problems during pregnancy, labor, or delivery that interrupt the baby’s oxygen supply.

Causes of HIE include:

• Placental abruption (placenta separating from the uterus before birth)
• Uterine rupture
• Umbilical cord problems (prolapse, compression, or tight nuchal cord)
• Severe maternal blood pressure problems
• Prolonged or difficult labor
• Shoulder dystocia

Babies with HIE may be born unresponsive, with poor muscle tone, absent or weak reflexes, and difficulty breathing. Some develop seizures in the first 24 hours. The severity of HIE ranges from mild (full recovery expected) to severe (high risk of death or permanent disability).

The most important treatment for moderate to severe HIE is therapeutic hypothermia, also called cooling therapy. Within six hours of birth, doctors cool the baby’s body temperature to about 92°F for 72 hours, which slows down the cascade of brain damage. This treatment has been proven to reduce death and disability, though it doesn’t eliminate all consequences.

Up to 50% of children with HIE that occurred at birth face long-term neurodevelopmental problems, including cerebral palsy, seizure disorders, developmental delays, and learning disabilities. Early intervention therapies starting in infancy improve outcomes significantly.

Why Do So Many Newborns Get Jaundice?

Jaundice, medically called hyperbilirubinemia, causes a baby’s skin and eyes to turn yellow. It’s extremely common, affecting up to 60% of premature babies and many full-term infants. Most cases are mild and resolve on their own, but severe jaundice can cause permanent brain damage if untreated.

Jaundice happens when bilirubin, a yellow pigment from the breakdown of red blood cells, builds up faster than the baby’s immature liver can process it. Risk factors include:

• Prematurity
• Blood type incompatibility between mother and baby
• Bruising during delivery
• Difficulty feeding in the first days
• Certain genetic conditions
• Infection

Doctors monitor bilirubin levels through blood tests. Treatment depends on how high the level rises and how quickly. Phototherapy, where special blue lights break down bilirubin in the skin, treats most cases requiring intervention. Babies receiving phototherapy lie under or on light-emitting pads, often wearing only a diaper and protective eye shields.

In rare cases where bilirubin reaches dangerous levels despite phototherapy, an exchange transfusion may be necessary. This procedure removes and replaces the baby’s blood to quickly reduce bilirubin. Untreated severe jaundice can cause kernicterus, permanent brain damage affecting movement, hearing, and development.

What Is Hypoglycemia in Newborns?

Hypoglycemia means the baby’s blood sugar level is too low. It’s particularly common in premature babies, infants of diabetic mothers, and babies who are small or large for their gestational age. The brain relies heavily on glucose for energy, so prolonged or severe hypoglycemia can cause brain damage.

In the womb, babies receive a constant glucose supply from the mother through the placenta. After birth, they must maintain their own blood sugar through feeding and internal glucose production. Some babies struggle with this transition.

Signs of hypoglycemia include:

• Jitteriness or tremors
• Poor feeding
• Lethargy
• Irregular breathing
• Seizures in severe cases

Many babies with hypoglycemia show no obvious symptoms, which is why NICU staff routinely check blood sugar in at-risk infants. Treatment begins with feeding, either breast milk, formula, or sugar water, depending on the baby’s ability to eat. Babies who can’t maintain normal glucose levels with feeding receive intravenous glucose solutions.

Most cases of newborn hypoglycemia resolve within days as the baby’s regulatory systems mature. However, persistent hypoglycemia may indicate an underlying condition requiring further evaluation and specialized treatment.

What Is Patent Ductus Arteriosus?

Patent ductus arteriosus (PDA) is a heart condition where a blood vessel called the ductus arteriosus, which is normal before birth, fails to close after delivery. About 30% of infants weighing less than 1,500 grams at birth have a PDA. While some small PDAs cause no problems, larger ones can lead to serious complications.

Before birth, the ductus arteriosus allows blood to bypass the baby’s non-functioning lungs. It normally closes within the first few days after birth when the baby begins breathing. In premature infants, this vessel often remains open because the mechanisms that trigger closure aren’t fully developed.

A PDA allows too much blood to flow to the lungs, making the heart and lungs work harder. Symptoms include:

• Difficulty breathing
• Poor weight gain
• Fast heart rate
• Heart murmur detected during examination
• Increased oxygen needs

Treatment options depend on the PDA’s size and the baby’s symptoms. Small PDAs may close on their own with watchful waiting. Medications like ibuprofen or indomethacin help close the ductus in many cases. If medications don’t work or the PDA is large and causing significant problems, surgery or catheter-based procedures can close it.

Most babies who receive appropriate treatment for PDA do well long-term, though some may have ongoing respiratory or cardiac issues depending on how severely their organs were affected before treatment.

Why Do Some Babies Have Trouble Feeding?

Feeding difficulties are extremely common in the NICU, affecting premature babies most severely. Successful feeding requires coordinating sucking, swallowing, and breathing, a complex skill that develops late in pregnancy. Babies born before 34 weeks typically can’t coordinate all three actions effectively.

Beyond prematurity, other conditions cause feeding problems:

• Neurological issues affecting muscle control or consciousness
• Gastrointestinal problems like NEC or reflux
• Breathing difficulties requiring respiratory support
• Fatigue from the work of being sick
• Congenital abnormalities affecting the mouth or digestive system

NICU babies often receive nutrition through a feeding tube placed through the nose or mouth into the stomach, bypassing the need for sucking and swallowing. As they mature and stabilize, they gradually transition to bottle or breast feeding. Some babies need special nipples, positioning, or feeding techniques.

Occupational and speech therapists work with NICU babies and families to develop safe feeding skills. Poor feeding delays discharge because babies must demonstrate they can take enough nutrition by mouth to grow before going home. Patience is essential, as feeding skills improve at different rates for each baby.

How Do Premature Babies Regulate Their Temperature?

Temperature instability is a significant challenge, especially for very low birth weight infants. Premature babies lose heat rapidly because they have thin skin, little body fat for insulation, and an immature ability to generate and conserve heat. Maintaining proper body temperature is critical because cold stress forces the baby to burn calories and oxygen to stay warm, potentially worsening other medical problems.

NICU staff place the smallest and youngest babies in incubators with carefully controlled temperature and humidity. The incubator environment adjusts based on the baby’s temperature, skin condition, and weight. As babies grow and mature, they gradually transition to open cribs with blankets.

Parents sometimes worry about the lack of clothing on their NICU baby, but minimal clothing in a warm incubator helps staff monitor the baby and prevents overheating. Skin-to-skin contact (kangaroo care) helps babies regulate temperature while providing numerous other benefits, including improved bonding, better breathing patterns, and enhanced feeding success.

What Birth Defects Send Babies to the NICU?

Congenital anomalies, or birth defects, range from minor issues requiring brief monitoring to life-threatening conditions needing immediate surgery. The NICU cares for babies with:

• Congenital heart defects, which affect nearly 1% of births and vary from minor holes that close on their own to complex malformations requiring multiple surgeries
• Gastrointestinal abnormalities including esophageal atresia, intestinal obstructions, and abdominal wall defects
• Neural tube defects like spina bifida
• Chromosomal conditions including Down syndrome, trisomy 13, and trisomy 18
• Kidney and urinary tract abnormalities
• Cleft lip and palate
• Skeletal abnormalities

Many birth defects are detected during pregnancy through ultrasound or other prenatal testing, allowing doctors to plan delivery at a hospital equipped to handle the baby’s needs immediately. Some defects aren’t apparent until after birth.

Treatment depends entirely on the specific condition. Some babies need surgery in the first hours or days of life. Others require medical management, specialized nutrition, or supportive care while their condition is monitored. The NICU team works with pediatric specialists, surgeons, and geneticists to provide comprehensive care.

What Are the Long-Term Outcomes for NICU Babies?

About 92% of babies admitted to the NICU survive to hospital discharge, a testament to advances in neonatal care. However, survival rates and long-term outcomes vary dramatically based on gestational age at birth, birth weight, and the specific complications each baby experiences.

Full-term babies admitted for brief stays due to temporary problems like jaundice or feeding difficulties typically have excellent long-term outcomes with no lasting effects. The picture becomes more complex for premature babies, especially those born before 28 weeks or weighing less than 1,000 grams.

Extremely premature infants face higher risks of:

• Cerebral palsy
• Developmental delays
• Vision problems including retinopathy of prematurity
• Hearing loss
• Chronic lung disease
• Learning disabilities
• Attention and behavioral challenges

The risk of significant neurodevelopmental impairment reaches 50% in babies with perinatal HIE and 25% in those with severe IVH. However, early intervention services including physical, occupational, and speech therapy significantly improve outcomes when started in infancy.

NICU graduates, particularly those born prematurely or with significant complications, need close developmental follow-up in the months and years after discharge. Many NICUs have developmental follow-up programs that track children’s progress and connect families with appropriate services. Not all NICU babies face long-term challenges, and many who do make remarkable progress with proper support.

Moving Forward After the NICU

Understanding the medical conditions affecting NICU babies helps families navigate their experience with greater confidence, though the emotional weight of watching your child fight for health never becomes easy. The problems discussed here represent the most common challenges, but each baby’s journey is unique. Today’s NICU teams use evidence-based protocols, advanced technology, and family-centered care approaches that have dramatically improved both survival and quality of life for the smallest and sickest newborns. While the statistics about complications and long-term outcomes can feel overwhelming, remember that behind every number are babies who thrive, families who heal, and medical teams dedicated to giving your child the best possible start in life.