THURSDAY, Feb. 26, 2026 (HealthDay News) -- Maternal tobacco smoking during pregnancy is a risk factor for increased childhood blood pressure (BP) and hypertension, according to a research letter published online Feb. 16 in Circulation.Lyndsey E. Shorey-Kendrick, Ph.D., from the Oregon Health & Science University in Beaverton, and colleagues examined the association of maternal tobacco smoking during pregnancy with childhood systolic and diastolic BP and hypertension. The analysis included 13,120 children born between 1999 and 2020 and participating in the Environmental Influences on Child Health Outcomes study.The researchers found that the prevalence of maternal tobacco smoking during pregnancy was 9.3 percent. Any maternal tobacco smoking during pregnancy was significantly associated with higher child diastolic BP (β = 0.09 U; 95 percent confidence interval [CI], 0.04 to 0.13; P < 0.001). However, there was no association for systolic BP (β = 0.05 U; 95 percent CI, –0.01 to 0.10). There was also an association between any maternal tobacco smoking during pregnancy and a significant increase in the incidence rate ratio for hypertension (without interaction, 1.54). Results were similar when adding preterm birth to models. Stronger effects were seen among girls than boys (diastolic BP: girls, 0.10; boys, 0.08; hypertension interaction term, 0.31). The effect was weaker on diastolic BP in younger children (younger than 6 years, 0.07; 6 years and older, 0.11), suggesting effects on BP may increase with age. "Our results suggest that decreasing maternal tobacco smoking during pregnancy may reduce prevalence of hypertension in children and therefore among adults, improving overall health," the authors write.Abstract/Full Text.Sign up for our weekly HealthDay newsletter