ECHO Cohort: Maternal Smoking in Pregnancy Linked to Higher Childhood BP

Recent research describes an association between maternal smoking during pregnancy (MSDP) and higher diastolic blood pressure and increased risk of hypertension in offspring, based on an analysis of the ECHO Cohort.

Prior studies often relied on self-reported smoking exposure or focused primarily on systolic blood pressure. The ECHO analysis examined associations with both systolic and diastolic blood pressure in children and additionally evaluated childhood hypertension as an outcome.

Investigators analyzed 13,120 children born from 1999 to 2020 across 52 ECHO Cohort Study sites in the United States, including Puerto Rico. Eligible participants had at least one blood pressure measurement between ages 3 and 18 and documentation of maternal smoking during pregnancy via self-report or medical record. In a subset of participants, maternal urine samples collected during pregnancy were analyzed for cotinine to define active smoking exposure. Children’s blood pressure measurements were converted to age-, sex-, and height-adjusted z scores, and hypertension was defined based on established pediatric thresholds across repeated visits.

In primary analyses, any maternal smoking during pregnancy was significantly associated with higher diastolic blood pressure in children but was not significantly associated with systolic blood pressure. Maternal smoking was also associated with an increased incidence rate of childhood hypertension. In the subset with biomarker data, cotinine-defined active smoking was associated with higher diastolic and systolic blood pressure in crude models and with increased risk of hypertension before and after covariate adjustment.

The report also describes variation across subgroups. Stratified analyses suggested stronger associations among female children compared with males. Age-stratified results indicated that associations with diastolic blood pressure were weaker in children younger than 6 years and stronger in those aged 6 years or older, suggesting that effects on blood pressure may increase with age. These findings are presented as observed patterns rather than mechanistic explanations.

Separately, self-reported secondhand smoke exposure during pregnancy was not associated with higher blood pressure z scores in children.

Key Takeaways:

• Maternal smoking during pregnancy was associated with higher diastolic blood pressure and increased risk of childhood hypertension in the ECHO Cohort.
• Associations were observed using both self-reported exposure and cotinine-defined active smoking, with hypertension risk persisting after covariate adjustment.
• Stronger associations were observed among female children, and effects on diastolic blood pressure appeared more pronounced in children aged 6 years or older.
• Self-reported prenatal secondhand smoke exposure was not associated with higher childhood blood pressure.