Respiratory distress syndrome (RDS) is a breathing condition that occurs when a baby’s lungs haven’t produced enough surfactant, a slippery substance that keeps the tiny air sacs in the lungs from collapsing. It primarily affects premature babies and is one of the most common reasons newborns need intensive care. About 50% of infants born between 26 and 28 weeks develop RDS, and roughly 25% of those born at 30 to 32 weeks are affected. The earlier a baby arrives, the higher the risk.
Why Premature Lungs Struggle
Inside the lungs, millions of tiny air sacs called alveoli inflate and deflate with every breath. Surfactant coats the inside of these sacs and prevents them from sticking shut when the baby exhales. Without it, the air sacs collapse after each breath, and the baby has to work extremely hard to re-inflate them every time. This is exhausting and unsustainable, and it quickly leads to dangerously low oxygen levels.
Surfactant is produced by specialized cells in the lungs that don’t fully mature until around 34 to 36 weeks of pregnancy. Babies born before that window simply haven’t had time to build up an adequate supply. Male infants are affected more often than females, and the condition also involves immature fluid-clearance channels in the lungs that make it harder to move liquid out of the airways after birth.
Signs That Appear Right After Birth
RDS typically shows up within minutes to hours of delivery. The hallmark signs are visible efforts to breathe: the baby’s nostrils flare open with each inhale, the skin between or below the ribs pulls inward (called retractions), and the baby makes a short grunting sound with each exhale. That grunting is actually the baby’s body trying to keep air pressure in the lungs so the air sacs don’t collapse completely.
Breathing is fast, often well above the normal newborn rate. In more severe cases, the baby’s skin may take on a bluish tint, especially around the lips and fingertips, signaling that not enough oxygen is reaching the bloodstream. Doctors listening with a stethoscope will hear diminished breath sounds, and peripheral pulses may be weaker than normal.
How Doctors Confirm the Diagnosis
A chest X-ray is the primary tool for confirming RDS. The classic finding is a hazy, washed-out look to both lungs, often described as a “ground glass” pattern. In mild cases, this appears as fine granular densities scattered across the lung fields. As severity increases, visible air-filled airways stand out against the opaque lung tissue. In the most severe form, the lungs appear almost completely white on the image.
These imaging findings help doctors distinguish RDS from a similar but much milder condition called transient tachypnea of the newborn (TTN). TTN happens when fluid left over from the womb isn’t absorbed quickly enough after birth. It’s far more common in babies delivered by cesarean section, resolves on its own, and usually only requires supplemental oxygen through a nasal tube. On X-ray, TTN shows prominent lung markings and sometimes fluid in the spaces between lung lobes, but not the ground-glass haziness of RDS. Babies with TTN also tend to breathe fast but don’t develop the severe retractions or grunting that characterize RDS.
Treatment in the NICU
The first line of support for a baby with RDS is continuous positive airway pressure, or CPAP. This delivers a gentle, steady stream of air through small prongs placed in the baby’s nostrils, keeping just enough pressure in the lungs to prevent the air sacs from collapsing between breaths. Current guidelines recommend starting CPAP from birth along with early surfactant therapy, with the goal of avoiding the need for a breathing tube whenever possible.
When surfactant needs to be given, doctors now have gentler options than in the past. The older approach required placing a breathing tube, delivering surfactant directly into the lungs, and then removing the tube (a method known as the INSURE technique). Newer methods, collectively called minimally invasive surfactant therapy, allow a thin, flexible catheter to be briefly guided into the airway while the baby continues breathing on CPAP. This avoids full intubation and mechanical ventilation in many cases. Multiple variations of this approach are now used in NICUs worldwide and have been shown to be safe and effective.
If a baby’s oxygen levels drop too low despite CPAP, or if blood gas measurements show dangerous levels of carbon dioxide and acidity, the medical team will move to mechanical ventilation with a breathing tube. This provides full respiratory support while the baby’s lungs mature and begin producing their own surfactant.
Survival Rates With Modern Care
Outcomes for babies with RDS have improved dramatically over the past several decades. By the 1990s, deaths specifically caused by RDS had become rare for infants weighing more than about 3.3 pounds (1,500 grams) at birth. In well-equipped NICUs today, an estimated 95% of premature infants above that weight who develop RDS can be saved with the combination of oxygen support, CPAP, surfactant, and mechanical ventilation when needed.
Among the very smallest and most premature infants (those classified as very low birth weight), roughly 15% do not survive, but the causes of death in high-resource settings have shifted away from RDS itself and toward other complications of extreme prematurity, including severe brain bleeds, intestinal disease, and chronic lung injury.
Preventing RDS Before Birth
The single most effective prevention strategy happens before the baby is born. When a pregnant person is at risk of delivering prematurely, doctors administer a course of corticosteroid injections. These steroids cross the placenta and accelerate lung maturation in the fetus, boosting surfactant production before delivery.
The American College of Obstetricians and Gynecologists recommends this treatment for pregnant individuals between 24 and 34 weeks of gestation who are at risk of delivering within seven days, including those with ruptured membranes and those carrying multiples. A separate course is also recommended between 34 and 37 weeks if preterm birth is likely and no previous course has been given. The benefits are substantial: in one large study, severe respiratory complications dropped from about 12% in the group that received a placebo to 8% in those who received steroids, a roughly one-third reduction. At the earliest gestational ages (23 to 25 weeks), steroid exposure before birth has been linked to meaningful reductions in death and long-term neurological problems.
Potential Long-Term Effects
Most babies who recover from RDS do well, especially those born closer to term. The primary long-term concern is bronchopulmonary dysplasia (BPD), a form of chronic lung disease that can develop in premature infants who needed prolonged oxygen or ventilator support. BPD results from inflammation and scarring in lungs that were still developing when they had to start working.
Babies who develop BPD may be more susceptible to respiratory infections throughout childhood, have reduced exercise tolerance, and in some cases develop high blood pressure in the blood vessels of the lungs. But the effects can extend beyond breathing. Children with BPD have a higher risk of cerebral palsy, developmental delays, lower IQ scores, and challenges with executive functioning and language development, both expressive and receptive. They also tend to need more specialist follow-up, therapy services, and hospitalizations during childhood, and some of these quality-of-life impacts persist into adulthood.
The severity of these outcomes depends heavily on how premature the baby was, how long they needed respiratory support, and how their individual development progresses. Many children with mild BPD outgrow their respiratory symptoms entirely, while those with more severe forms benefit from ongoing monitoring and early intervention services.