Does NICU Oxygen Therapy Cause Retinopathy of Prematurity?

The relationship between oxygen therapy and Retinopathy of Prematurity (ROP) is complex. It is completely normal to feel anxious or guilty if your baby is receiving oxygen support, especially if you have heard that oxygen causes ROP. While extreme prematurity is the primary underlying risk factor, the amount, duration, and stability of oxygen exposure do modify that risk ^[1][2]. However, the oxygen your baby receives in the NICU is life-saving, and doctors must carefully balance the need to support your baby’s survival and overall health with the risk of ROP.

Why an Immature Retina Raises the Risk

The blood vessels in a baby’s retina (the light-sensitive back part of the eye) grow gradually during the last 12 weeks of pregnancy. Because fetal oxygen levels in the womb are naturally lower than oxygen levels outside the womb, premature birth interrupts this normal, tightly regulated vascularization process ^[1]. Because the retina is only partially covered with blood vessels at birth, it is highly vulnerable.

The earlier a baby is born and the less they weigh, the higher their baseline risk of developing ROP. Even with careful oxygen management, extreme prematurity leaves a substantial baseline risk ^[3][4].

The Two-Phase Mechanism of ROP

To understand how oxygen interacts with your baby’s developing eyes, it helps to know how ROP develops in two distinct phases:

1. Phase 1: Paused Vessel Growth. Right after birth, the baby is exposed to the outside world, which has more oxygen than the womb environment. If supplemental oxygen is needed, this relatively higher oxygen level can suppress the normal growth of retinal blood vessels and cause some fragile new vessels to shrink or vanish ^[1][5].
2. Phase 2: Abnormal Vessel Growth. As the baby grows over the next few weeks, their retina matures and its energy and oxygen needs rise. Because the blood vessels paused their growth during Phase 1, the edges of the retina become starved for oxygen ^[1][5]. The oxygen-starved peripheral retina releases chemical signals, such as VEGF (Vascular Endothelial Growth Factor), which stimulate new blood vessels to grow. Unfortunately, these new vessels are often abnormal, leaky, and grow in the wrong direction, which is the hallmark of ROP ^[5][6].

Additionally, wide fluctuations in oxygen levels—bouncing back and forth between too high and too low—can stress the developing eyes and may contribute to ROP ^[7][8].

The Life-Saving Balancing Act

Historically, unmonitored and very high levels of oxygen caused severe cases of ROP. Today’s neonatal care uses continuous monitors (pulse oximeters) and oxygen blenders to maintain a carefully adjusted target range ^[9][10]. Oxygen saturation (the percentage of oxygen in the blood, shown on the monitor) is continuously tracked to keep levels as stable as possible.

Doctors are constantly performing a delicate balancing act. Large medical studies have shown that intentionally targeting lower oxygen saturation can reduce the risk of severe ROP that requires treatment, but this lower oxygen target significantly increases the risk of mortality and severe gut problems, such as necrotizing enterocolitis (NEC) ^[11][12][13].

Therefore, your baby’s care team carefully calibrates oxygen targets to protect your baby’s life, brain, lungs, and gut, while striving to minimize the risk to their eyes ^[11][13].

Screening and Next Steps

Because ROP often has no visible outward symptoms, premature infants are routinely screened by an ophthalmologist based on their birth weight and gestational age ^[3][1]. Screening timing depends on your baby’s postmenstrual age (their gestational age at birth plus the weeks since birth).

Many cases of mild ROP improve on their own without treatment. If the eye doctor diagnoses sight-threatening ROP, they may recommend treatments such as laser therapy or injection medicines to stop the abnormal vessel growth. It is crucial to attend every scheduled eye exam, even after your baby is discharged from the NICU, as ROP can continue to evolve.

What you can do:

• Never adjust your baby’s oxygen settings yourself; always ask the medical team.
• Ask the team to explain your baby’s specific target oxygen range and how they manage alarms.
• Ensure all eye exams are scheduled and attended.