The majority of preterm births stem from chorioamnionitis. (Stock photo)
The vast majority of preterm births—especially “micro-preemies” born at 22 or 23 weeks’ gestation—stem from a single cause: chorioamnionitis, an inflammation of the placenta and membranes surrounding the fetus. But Children’s of Alabama neonatologist Viral Jain, M.D., is on a mission to determine why this insidious condition occurs, the ways it affects babies’ health, and how to stop it.
Occurring in an estimated 1% to 5% of births in the United States, chorioamnionitis—often shortened to chorio—can be hard to spot. It’s typically diagnosed using clinical signs of inflammation such as fever or elevated heart rates in either the mother or the baby. But chorio often eludes clinical diagnosis, silently causing damage to the placenta and triggering preterm birth, says Jain, also an assistant professor in the Division of Neonatology at the University of Alabama at Birmingham (UAB).
“It’s a huge reason why neonatology exists, as such,” he explained. “It’s the body’s reaction when there’s inflammation to deliver the baby preterm, and all the complications that come with a preterm baby are due to chorio. In addition, the inflammation also causes direct damage to the developing organs of the baby.”
Some of the extensive research conducted on chorio has focused on its causes, which may include infection, environmental chemicals, smoking and bleeding. But scientists still have a poor understanding of why it happens, Jain notes, as well as how to catch it early enough to stop premature delivery.
Much of Jain’s research has delved into chorio’s potential health implications for babies once they’re born—and the effects can be devastating. One of his studies shows that the incidence of cerebral palsy is far higher in infants born when chorio progresses to such a severe extent it becomes funisitis, or inflammation of the umbilical cord. Jain’s findings have been somewhat controversial, he acknowledges, since cerebral palsy is already known to affect more preterm infants than those born after full-term pregnancies.
“We chose the most severe chorio babies for the study to clearly show that it affects cerebral palsy development,” Jain said. “We found that it’s about 50-50—so half the risk of cerebral palsy was from being born pre-term due to chorio, and half was the direct injury coming from inflammation to the developing brain.”
To help predict the cerebral palsy risk of these infants while they’re still in the neonatal intensive care unit (NICU)—when early intervention can more easily be planned—Jain’s research has also used MRI to look for specific markers in the brain suggesting a high risk of the disabling condition.
“We showed that chorioamnionitis insult, which started at birth, continues in these babies and that we can see those changes in the MRI and that they lead to cerebral palsy,” he said. “This means you can start early intervention on those babies to capture or reduce some of the damage.”
Another of Jain’s studies suggests that infants born early due to chorio have chronic lung damage. “It creates an immune cell dysfunction in the lung that there is continuous damage happening,” he explained. In addition to requiring longer ventilator and oxygen treatment, these babies “end up developing what we call BPD, or bronchopulmonary dysplasia, which is neonatal chronic lung disease.”
Ultimately, Jain says, his research—which has been funded by the American Heart Association and National Institutes of Health—seeks to learn how chorio propagates so doctors can impede its damage.
“The goal is to find out what treatment we can give so when it’s just mild we can stop the progression and it won’t become full-blown chorio and end up delivering the baby preterm,” he said. “If we can do that, we can prevent a lot of organ damage to the lung or brain.”
For more information on Jain’s work on chorio, listen to this episode of the Children’s of Alabama PedsCast podcast.
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