A large study published in the Journal of American Association for Pediatric Ophthalmology and Strabismus found that preterm infants born to mothers with a diagnosed marijuana use disorder were no more or less likely to develop retinopathy of prematurity (ROP) than those born to mothers without such a diagnosis.
Researchers from the University of California San Diego analyzed data from 31,110 singleton preterm births recorded between 2011 and 2020 using the university’s Study of Outcomes in Mothers and Infants database. The study focused specifically on infants born between 22 and less than 31 weeks’ gestation, and/or those weighing under 1,500 grams at birth, who survived long enough to undergo standard ROP screening.
Among the 997 infants born to mothers with a marijuana use disorder diagnosis during pregnancy, 32.1% developed ROP. This was nearly identical to the 33.3% rate observed among the 30,113 infants whose mothers did not have such a diagnosis. After adjusting for numerous maternal demographic and clinical factors, including smoking, alcohol use, anxiety, depression, hypertension, and socioeconomic indicators, researchers found no statistically significant difference in risk. The adjusted relative risk was 1.0, with a 95% confidence interval of 0.9 to 1.1.
The study also examined more serious cases of the condition. Severe ROP occurred in 4.5% of infants born to mothers with a marijuana use disorder, compared to 5.0% among those without. This difference was also not statistically significant after adjustment.
ROP is a potentially blinding disorder caused by abnormal retinal blood vessel development in premature infants. It is one of the leading causes of preventable childhood vision impairment in the United States. While previous research has shown that maternal marijuana use is associated with preterm birth and low birth weight—both known ROP risk factors—this analysis found that marijuana use disorder itself did not independently influence ROP risk once those and other variables were accounted for.
The authors note several limitations, including reliance on diagnostic codes to identify marijuana use disorder, which does not capture frequency, timing, method of use, or total exposure. They also caution that racial disparities in drug screening practices during pregnancy could influence who receives such diagnoses in hospital records.
Still, given the growing prevalence of marijuana use during pregnancy in the United States, the researchers say the findings help clarify at least one potential neonatal outcome that does not appear to be directly affected.
The full study is available by clicking here (PDF).
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