NICU Glossary: Common Terms Every NICU Parent Should Know

When you first walk into the NICU, it can feel like everyone around you is speaking a different language. Doctors and nurses move quickly, using terms and abbreviations that mean nothing to a terrified parent standing at their baby's bedside.

I know that feeling firsthand.

This glossary is the resource I wish I'd had. Plain-language definitions for the most common NICU terms - no medical degree required. Bookmark this page, screenshot it, share it with your partner or family. You deserve to understand everything that's happening with your baby.

Bradycardia (Brady) A temporary slowing of your baby's heart rate below normal. Bradys are extremely common in premature babies and are usually self-resolving - meaning your baby brings their heart rate back up on their own. When they don't, nurses will gently stimulate your baby. Bradys are frightening to witness but are a normal part of prematurity.

Apnea A pause in breathing lasting more than 15-20 seconds. Like bradys, apnea is very common in preemies whose brains are still developing the automatic signal to breathe. Often referred to together as "A's and B's" (apnea and bradycardia).

Desaturation (Desat) When your baby's oxygen saturation drops below the target range. You'll hear alarms and see the oxygen number on the monitor drop. Nurses watch these closely and adjust oxygen support as needed.

O2 Sat / SpO2 Oxygen saturation - the percentage of hemoglobin in the blood carrying oxygen. In the NICU, the target range is typically 90-95% for premature babies, though this varies by baby and gestational age.

CPAP (Continuous Positive Airway Pressure) A form of non-invasive breathing support that delivers a constant flow of air pressure to keep your baby's airways open. Your baby breathes on their own but gets help keeping their lungs inflated.

High-Flow Nasal Cannula A small tube placed under the nose that delivers humidified, heated air at a higher flow rate than standard oxygen. A step down from CPAP, used as babies improve.

Ventilator (Vent) A machine that breathes for your baby or assists their breathing through a tube placed in the airway (intubation). Used when babies need more support than CPAP can provide.

Intubation The placement of a breathing tube through your baby's mouth or nose into their airway, connected to a ventilator. Sounds scary - but it's a lifesaving intervention when babies need it.

Extubation The removal of the breathing tube. Usually a milestone worth celebrating.

PICC Line (Peripherally Inserted Central Catheter) A thin, flexible tube inserted into a vein in your baby's arm, leg, or scalp that extends to a large vein near the heart. Used to deliver nutrition, medications, and fluids over a longer period without repeated needle sticks.

UAC / UVC (Umbilical Arterial/Venous Catheter) Catheters placed in the umbilical cord shortly after birth. Used in the earliest, most critical days to deliver fluids, nutrition, and medications and to draw blood without painful needle sticks.

NG Tube / OG Tube (Nasogastric / Orogastric) A thin tube passed through the nose or mouth into the stomach used to deliver breast milk or formula when babies aren't yet able to feed by mouth.

IV (Intravenous Line) A small needle or catheter placed in a vein to deliver fluids and medications directly into the bloodstream.

TPN (Total Parenteral Nutrition) Intravenous nutrition delivered directly into the bloodstream. Used when babies are too small or too sick to digest milk yet. Contains proteins, sugars, fats, vitamins, and minerals.

Colostrum The first milk produced after birth - small in volume but incredibly powerful. Packed with antibodies and nutrients, it's often called "liquid gold." Even drops of colostrum matter enormously for your NICU baby.

Fortifier A powder or liquid added to breast milk to increase its calorie and nutrient content. Common for premature babies who need extra calories to grow.

Nippling When your baby begins practicing feeding from a bottle or breast. A major developmental milestone in the NICU.

Jaundice / Hyperbilirubinemia A yellowing of the skin and eyes caused by a buildup of bilirubin as the liver matures. Treated with phototherapy (special blue lights). Very common and very treatable.

RDS (Respiratory Distress Syndrome) A breathing condition common in premature babies whose lungs haven't produced enough surfactant - the substance that keeps air sacs open. Treated with surfactant therapy and breathing support.

NEC (Necrotizing Enterocolitis) A serious intestinal condition that can affect premature babies where intestinal tissue becomes inflamed or begins to die. Treated with antibiotics, bowel rest, and sometimes surgery. A diagnosis NICU parents hope to never hear but should understand.

IVH (Intraventricular Hemorrhage) Bleeding in or around the brain's ventricles. Graded on a scale of 1-4, with Grade 1-2 often resolving without intervention and Grade 3-4 requiring closer monitoring. Head ultrasounds are routine in premature babies to screen for this.

PDA (Patent Ductus Arteriosus) A blood vessel near the heart that normally closes after birth but sometimes remains open in preemies, affecting blood flow. Can be managed with medication or, less commonly, surgery.

Sepsis A serious bloodstream infection. Premature babies have immature immune systems making them more vulnerable. NICU teams watch carefully for signs and treat aggressively with antibiotics.

Gestational Age (GA) How far along the pregnancy was when your baby was born, measured in weeks. A baby born at 28 weeks GA will have different needs than one born at 34 weeks.

Corrected Age / Adjusted Age Your baby's age calculated from their original due date rather than their birth date. Used when tracking development and milestones for premature babies - typically until age 2. A baby born 2 months early is "2 months behind" developmentally and that's completely normal.

Kangaroo Care Skin-to-skin contact where your baby is placed chest-to-chest on a parent's bare skin. One of the most powerful things you can do for your baby - it regulates their temperature, heart rate, and breathing, reduces stress, and supports bonding and breastfeeding.

Care By Parent / Primary Nursing When parents take on more hands-on care tasks as their baby grows stronger. A sign you're heading toward discharge!

Isolette / Incubator The clear enclosed bed your premature baby lives in that regulates temperature and humidity. Also called a warmer in open-bed form.

Open Crib When your baby graduates from an isolette to an open crib - a sign they can regulate their own body temperature. A major milestone!

Discharge Criteria The set of goals your baby needs to meet before going home. Typically includes: maintaining body temperature, feeding by mouth, and breathing without support.

The NICU has hundreds of abbreviations, nicknames, and medical terms - and every unit has its own shorthand too. This glossary grows with your help.

If you heard a term during your NICU stay that left you confused, googling at 2am, or wishing someone had just explained it plainly - we want to hear it.

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We'll research it, write a plain-language definition, and add it to this glossary so the next NICU parent doesn't have to feel as lost as we did.

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I'm Louie, a NICU parent who started Between Beeps because no family should navigate the NICU feeling alone and confused. Every week I share support, education, and real talk for NICU families — during your stay and beyond.

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You're doing an incredible job. Keep going.

— Louie