When Kristi, a Nebraskan mother, took multiple common medications during her pregnancy, she followed her doctor's guidance. Years later, when her son was diagnosed with autism spectrum disorder, she wondered if there was a connection. A groundbreaking new study may finally offer some answers—not just for her, but for millions of families across the United States.
Researchers at the University of Nebraska Medical Center have conducted the largest-ever investigation into how certain prescription medications taken during pregnancy might influence autism risk in children. Analyzing 6.14 million maternal-child health records from the Epic Cosmos database—representing nearly one-third of all U.S. births between 2014 and 2023—the team identified a consistent association between medications that inhibit cholesterol synthesis and higher rates of autism diagnosis in offspring.
These sterol biosynthesis-inhibiting medications, or SBIMs, include some of the most frequently prescribed drugs in America: common antidepressants like sertraline and fluoxetine, antipsychotics such as aripiprazole, beta-blockers including metoprolol and propranolol, and widely-used statins like atorvastatin. Together, these 14 medications account for more than 400 million prescriptions annually. The researchers deliberately grouped them by their biochemical effects rather than by what they treat—an approach that revealed patterns invisible to traditional analysis.
The findings show that mothers prescribed at least one SBIM during pregnancy faced a 1.47-fold higher risk of having a child later diagnosed with ASD. That risk climbed progressively: each additional concurrent SBIM increased the risk by a factor of 1.33, reaching 2.33-fold when four or more were prescribed simultaneously. Among the 196,447 children diagnosed with ASD in the cohort, 14.2 percent had prenatal SBIM exposure. Perhaps most striking, SBIM use during pregnancy nearly quadrupled over the study period, rising from 4.3 percent of pregnancies in 2014 to 16.8 percent in 2023.
Why does cholesterol matter so much? The fetal brain begins producing its own sterols around 19 to 20 weeks of gestation, and cholesterol is essential for proper neurological development. Genetic disruptions to this pathway are known to cause severe developmental syndromes; in Smith-Lemli-Opitz syndrome, up to 75 percent of children meet criteria for ASD. The UNMC team's work is the first nationwide study to evaluate how common medications might unintentionally interfere with this critical process.
Senior author Dr. Karoly Mirnics, dean and director of the UNMC Munroe-Meyer Institute, is careful to emphasize what the findings do not mean. "Our findings do not suggest that these medications are unsafe for adults," Mirnics said. "But they raise important questions about their use during pregnancy, a period when even small biochemical disruptions may have outsized effects on fetal brain development." The researchers stress that no pregnant patient should discontinue or alter medication without medical supervision—many SBIMs are essential, often life-saving treatments.
Instead, the study serves as a call to action. The team proposes creating a comprehensive list of medications with sterol-inhibiting effects, evaluating new drugs for these properties before approval, educating healthcare providers about safer prescribing during pregnancy, and investing in research to develop alternatives that protect both maternal health and fetal development. For families like Kristi's, this work offers not immediate answers but something equally valuable: a clearer path forward.