Researchers Design Simulation to Better Understand Newborn Retinal Hemorrhaging
Model Reveals Condition is Caused by Compression during Labor
Florida Tech Ph.D. candidate Jose Colmenarez and his advisor, professor of biomedical engineering Linxia Gu, are on a mission to expand clinicians’ understanding of why many infants experience retinal hemorrhaging in childbirth. In their latest research, published in Scientific Reports, they found that the condition is caused by pressure exerted during labor — which challenges existing theories for its cause — using a detailed computer model they developed to map the condition’s mechanics.
In their paper, “Vascular insult in neonatal retinal hemorrhage: computational analysis of a fundus-segmented blood vessel network,” the researchers wrote that as many as half of all newborns experience physiologic retinal hemorrhaging, or bleeding in the retina caused naturally. The highest percentage of cases was found in births that required instruments, such as a vacuum suction, to assist in delivery.
Colmenarez and Gu, along with a team of researchers from the University of California-Irvine, wanted to find out exactly how this injury is caused. So, they simulated what happens when the pressures exerted during labor push against fetal eye structures.
Because the injury happens during childbirth and involves infants, Colmenarez said testing can be invasive or unethical. Using a computer model that simulated the process was a much less invasive alternative.
“With newborns, it’s difficult to experiment, it’s not ethical,” Colmenarez said. “So that’s why [clinicians] asked us to create a theoretical model that may explain the process that is happening during labor.”
Colmenarez’ model directly simulated a fetus’ eye, optic nerve, eye socket and retinal vessels during labor. He found that stress and strain on the eye during contractions, which compress a fetus’s head, caused eye deformation. If tiny vessels experience too much tension for too long, he said, they can rupture and cause hemorrhaging.
His results challenge the existing idea that vein occlusion at the optic nerve causes the hemorrhage, as it wasn’t observed in the model, he stated.
“During labor, contractions can last one minute. So, it’s one minute under very high pressure that’s exerted on the eye,” Colmenarez explained. “With maximum compression like this, retinal vessels reach a stress limit and rupture.”
Colmenarez hopes the model can help clinicians understand the basic mechanics behind retinal hemorrhaging. He said knowing how much force causes bleeding can help establish a threshold for how much force a fetus can withstand. He also believes that this information can guide research into safer instruments to assist in delivery.
