What Is Car Seat Test for Newborns? | What Parents Should

You’ve probably heard about car seat tests for newborns and assumed every baby gets one before leaving the hospital. That assumption is understandable but not quite accurate—the test is reserved for specific infants, not all newborns.

The car seat test (also called a car seat tolerance screening or car seat challenge) is a medical assessment used for preterm and low-birth-weight babies. It checks whether they can maintain stable breathing, heart rate, and oxygen saturation while sitting semi-reclined in their car seat. Here’s what the test involves and why it matters for some newborns.

What Is a Car Seat Test for Newborns?

The car seat test is a predischarge evaluation that monitors vital signs while the baby sits in their own car seat. The American Academy of Pediatrics (AAP) recommends it for infants born before 37 weeks of gestation or weighing less than 5 pounds 8 ounces (2,500 grams).

The test addresses a specific concern: preterm infants may experience apnea (pauses in breathing), bradycardia (slow heart rate), or oxygen desaturation when placed in a semi-reclined position. The typical test runs 90 minutes or longer, with continuous monitoring by a pulse oximeter and cardiorespiratory monitor.

Full-term, healthy-weight newborns generally do not require the test. According to the AAP guidelines, the car seat test for newborns is a targeted safety check, not a universal requirement.

Why the Test Exists for Some Babies

Parents of preterm or low-birth-weight infants often worry about breathing issues during car rides. The test exists because the semi-reclined car seat angle can compress a small baby’s airway or cause positional apnea. Here are the key reasons hospitals screen certain infants:

• Risk of apnea: Preterm babies have immature respiratory control centers in the brain, making them more prone to pauses in breathing, especially when positioned at a 45-degree angle.
• Oxygen desaturation: Even modest drops in oxygen levels, if repeated, may affect long-term neurodevelopment. The test captures these episodes before discharge.
• Bradycardia episodes: A slow heart rate often accompanies apnea in preterm infants. The test monitors heart rate alongside breathing.
• Positional vulnerability: A 2016 study found that adjusting the car seat angle from 45° to 30° resolved desaturation issues in 18 of 29 infants who initially failed the test.
• Medical conditions: Full-term babies with conditions requiring NICU care—such as congenital heart defects or respiratory issues—may also need screening per CHOP recommendations.

The test isn’t meant to scare parents—it’s designed to catch problems that can be corrected with simple adjustments like repositioning or choosing a different car seat model.

How the Test Works

The baby is placed in their own car seat, which is then positioned on a hospital cart or a hard surface to mimic the angle of a car seat base. The seat must be within the hospital building—tests are not conducted inside vehicles unless special arrangements exist.

Medical staff attach a pulse oximeter to the baby’s foot or hand to measure oxygen saturation, along with electrodes on the chest to track heart rate and breathing. The baby remains in the seat for the full test duration, typically 90 to 120 minutes. The Ohio State Wexner Medical Center explains the full car seat test monitoring process in its patient education materials.

The baby passes if all vital signs stay within normal range for the entire test. If oxygen levels drop, heart rate slows significantly, or breathing stops for more than a few seconds, the baby fails. The test is performed by trained nursing staff, not by car seat technicians, and hospitals do not install car seats for families.

Who Needs the Test and What Happens If They Fail

Determining which babies get tested follows clear guidelines, but what happens if a baby fails can vary. Here’s a step-by-step look:

1. Identify candidates: The AAP recommends testing for all infants born before 37 weeks or weighing less than 5 pounds 8 ounces. Babies with certain medical conditions are also considered.
2. Perform the screen: The test lasts 90 minutes or more, with continuous monitoring. Some hospitals run it during a feeding to help keep the baby settled.
3. Evaluate results: If the baby passes, they are cleared for travel. If they fail, the care team tries interventions—adjusting the car seat angle, using a different seat model, or adding rolled blankets for positioning support.
4. Offer retesting: After adjustments, the test may be repeated. Many babies pass on the second attempt after simple changes.
5. Recommend alternatives: If repeated failures occur, the team may suggest a car bed—a flat, reclined device that allows the baby to lie more horizontally during transport.

A failed test does not mean the baby cannot go home; it means the team works to find a safe travel solution before discharge.

These thresholds are typical; individual hospitals may adjust based on their protocols and the baby’s specific needs.

The Evolving Evidence Behind Routine Screening

While the AAP and ACOG currently recommend car seat tolerance screening for preterm infants, some recent research questions whether routine testing improves outcomes or may cause unintended delays. A 2026 study in JAMA Network Open found that routine screening before discharge may prolong hospitalization when infants fail, without clear evidence of improved postdischarge outcomes.

Another 2026 study concluded that routine CSTS in preterm or at-risk full-term infants may not improve outcomes, calling the practice into question. A separate study found that discontinuing predischarge car seat tolerance screenings for premature infants did not cause those children harm. The evidence is still evolving, and professional organizations are reviewing current guidelines.

Per the AAP ACOG car seat test guidelines from the Wisconsin NICU program, the test remains standard for preterm and low-birth-weight infants. However, parents should understand that the practice is under active reevaluation.

These studies do not mean the test is useless—they suggest that for many infants, the risks of prolonged hospitalization may outweigh the screening benefits.

The Bottom Line

The car seat test for newborns is a valuable tool for identifying breathing, heart rate, and oxygen problems in preterm and low-birth-weight infants before they go home. Current AAP guidelines support its use, but newer evidence suggests the practice may need refinement. If your baby is born early or small, expect the hospital to perform this test—and know that a failed test leads to solutions, not a delay in discharge home.

For specific guidance on your baby’s situation, ask the neonatologist or discharge nurse whether the car seat test is indicated based on your child’s gestational age, birth weight, and medical history. Every hospital follows slightly different protocols, so clarifying expectations before discharge helps reduce surprises on the big day.