Because their eyes are not fully developed at birth, premature infants are at risk of abnormal eye development.  The part of the eye most at risk of aberrant development is the retina—the back layer of the eye that is sensitive to light and that triggers nerve impulses that pass onto the brain. 

The most common eye disorder that preemies develop is known as retinopathy of prematurity. The word retinopathy means a disease of the retina. The disorder is commonly called by its abbreviation–ROP.  The more premature the baby, the higher is the risk of developing ROP. Most of the babies who develop ROP are born more than 2.5 months early. About 60,000 babies in the U.S. are at risk for ROP each eyar. 

ROP is a leading cause of blindness in preemies around the world. For many decades, it has been known that high oxygen levels can cause ROP.  For this reason, as little oxygen as necessary is administered to premature babies. However, there are many other factors, in addition to oxygen, that also influence development of the eye.  Zietchick Research Institute has discovered that levels of hCG—also known as the “pregnancy hormone”– helps determine whether or not a premature infant will develop retinopathy. 

Researchers at Zietchick Research Institute measured hCG levels in over 100 premature infants.  The levels of hCG in newborn, premature infants are extremely small. Special high tech equipment was utilized to perform the measurements.  The technology that the scientists used—MesoScale Discovery Platform—is able to detect hormone, proteins and other substances that as low as one billionth of a gram. They found that at 4 weeks old, blood levels of hCG are lower in premature babies who develop the disease compared to those who don’t.  This is true for both girls and boys. 

This is a very important finding since it will inspire new treatments to prevent eye disease in preterm infants.  It has been known for a long time that hCG helps promote the development of blood vessels in the uterus during pregnancy. Without adequate levels of hCG, pregnancy cannot be sustained.  But… it hasn’t been known that hCG help promote development of blood vessels in the retina. In the future, Zietchick researchers will study whether supplementing babies with hCG helps premature infants develop healthier eyes with better vision.  Besides the eyes, there are hCG receptors in many other organs as well such as the brain, lung and gut. Premature infants often have problems with these organs as well. Therefore, scientists should also study the relationship between hCG and the other organs which may be affected by this hormone.  


The postnatal presence of human chorionic gonadotropin in preterm infants and its potential inverse association with retinopathy of prematurity. Movsas TZ, Paneth N, Gewolb IH, Lu Q, Cavey G, Muthusamy A. Pediatr Res. 2019 Sep 19.. [Epub ahead of print] PMID: 31537012