Purpose: Prior studies examining the risk of retinoblastoma with maternal smoking were inconclusive, likely due in part to the reliance on self-reported maternal smoking. This study uses biomarkers of tobacco smoking in neonatal dried blood spots to investigate associations between maternal smoking and retinoblastoma in offspring.

Methods: We randomly selected 498 retinoblastoma cases and 895 controls born between 1983-2011 from a population-based case-control study in California. Maternal pregnancy-related smoking was measured using the following 3 metrics: provider or self-reported smoking during pregnancy, cotinine, and hydroxycotinine in neonatal blood. We employed multivariable logistic regression to estimate the effects of maternal tobacco smoking on retinoblastoma.

Results: Using all metrics (biomarkers or self-report), maternal smoking late in pregnancy or early postpartum was related to retinoblastoma [all types; Odds Ratio (OR)=1.44, 95% Confidence Interval (CI) 1.00, 2.09]. Relying on cotinine or hydroxycotinine to ascertain smoking, maternal smoking was related to unilateral retinoblastoma (OR=1.66, 95% CI 1.08, 2.57).

Conclusion: The results indicate that maternal smoking during pregnancy may be a risk factor for retinoblastoma, particularly among unilateral cases.