Researchers at the University of Kentucky are shedding light on an understudied aspect of today’s opioid crisis: What happens to the cardiovascular health of babies exposed to opioids in the womb?

The new study suggests that children born to mothers who use opioids during pregnancy may be more likely to develop chronic diseases as adults, including cardiovascular and metabolic diseases. Researchers presented their work over the weekend at the American Physiology Summit, the flagship annual meeting of the American Physiological Society (APS), in Long Beach, California.

Opioid abuse is a key public health challenge in Kentucky and the U.S., which saw over half a million opioid-related overdose deaths in 2022 alone. The use and misuse of opioids during pregnancy have grown rapidly over the past decade. On average, about one baby born every 15 minutes in the U.S. is diagnosed with neonatal opioid withdrawal syndrome (NOWS), an array of symptoms stemming from opioid use during pregnancy.

Although the symptoms of NOWS are usually treatable in babies, scientists have known little about the potential long-term health impacts of in-utero opioid exposure once these children grow up.

“It is challenging to predict the long-term impact on the cardiovascular health of children from women with opioid misuse and opioid overdoses due to the lack of follow-ups after discharge,” said Analia Loria, Ph.D., senior study author and an associate professor in the Department of Pharmacology and Nutritional Sciences in the UK College of Medicine. “However, our studies provide insights regarding how opioids could affect the programming of the mechanisms regulating cardiovascular function and increase the cardiovascular risk.”

The researchers developed a rat model that mimics the use of drugs during pregnancy and studied what happens to the offspring from birth until adulthood. They found that babies of mothers who used drugs while pregnant were shorter at birth and weighed less during the breastfeeding stage compared to nondrug-exposed babies. However, when they started eating independently, the drug-exposed babies gained weight quickly and caught up to their nonexposed peers, a pattern that has previously been found to increase the risk of cardiovascular and metabolic disease.

“Overall, we found that the systems that control blood pressure and how sugar and lipids are processed in our bodies are altered in drug-exposed babies,” said Nermin Ahmed, a registered dietitian and doctoral candidate in pharmacology and nutritional sciences. “This could mean that adults who were exposed to drugs in the womb are more likely to develop chronic diseases like high blood pressure, diabetes, chronic kidney disease and high cholesterol, and they may also be more susceptible to other drugs and environmental stressors. This prenatal exposure can permanently change how the body handles a second exposure to opioids.”

As adults, rats exposed to drugs in the womb had higher blood pressure, poorer blood sugar control and increased levels of bad cholesterol despite eating the same type of diet as the nondrug-exposed rats. The researchers also observed differences in the expression of certain proteins and receptors involved in regulating how the brain responds to drugs, raising the possibility that people exposed to opioids in the womb may also face a higher risk of drug dependence later in life. 

The study draws attention to the effects of the opioid epidemic on childbearing women and the importance of screening for prenatal opioid exposure. Researchers say that knowing more about such exposures could help to inform disease prevention and treatment approaches throughout the lifespan.

You can find the full study published in the American Heart Association’s journal Hypertension online here.

About the American Physiological Society
Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.

Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number P20GM103527. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.