A new longitudinal study published in the Journal of the American Heart Association has confirmed that children born to mothers who smoked during pregnancy have a significantly higher risk of developing high blood pressure by early adolescence.
The findings suggest that intrauterine tobacco exposure has long-lasting effects on cardiovascular regulation, independent of postnatal lifestyle or environmental factors.
The study, which utilized data from the Longitudinal Study of Australian Children (LSAC) and the Child Health CheckPoint study, assessed the cardiovascular health of 1,582 mother-child pairs using standardized biometric measures.
Key Study Highlights
- Children exposed to maternal smoking during any trimester had significantly higher systolic blood pressure (SBP) and mean arterial pressure (MAP) by age 11–12.
- Maternal smoking of more than 10 cigarettes per day was linked to nearly double the odds of adolescent hypertension.
- A dose-response relationship was observed between smoking intensity and increases in SBP, DBP, and MAP.
- Children of mothers who smoked throughout pregnancy had a 64% greater risk of hypertension.
- No strong associations were found with arterial stiffness or carotid thickness, suggesting blood pressure is the most sensitive marker in early life.
Contents
Study Overview: Prenatal Tobacco Exposure and Pediatric Cardiovascular Risk
The data came from two major population studies in Australia designed to follow health trends from infancy through adolescence.
The LSAC birth cohort, launched in 2004, tracks children biennially beginning at ages 0 to 1.
By wave 6 in 2014, children aged 11–12 were invited for a clinic visit with their caregiver.
Between 2015 and 2016, the Child Health CheckPoint study collected comprehensive biosamples and cardiovascular measurements.
This nested analysis focused on 1,582 mother-child dyads who completed physical assessments and reported maternal health behaviors during pregnancy.
Read also: Smoking And High Blood Pressure (Hypertension): Is There A Connection?
Maternal Smoking Patterns and Classification
Smoking exposure was defined by three variables: ever smoked during pregnancy, average daily intake (≤10 vs >10 cigarettes), and whether smoking continued throughout all trimesters.
Among the sample, 11.8% of mothers (n=187) smoked at some point during pregnancy.
Within that group, 76.5% smoked continuously, and 31.0% exceeded 10 cigarettes per day, meeting the study’s high-intensity threshold.
These exposure groups were compared to non-smoking mothers to assess risk differentials in cardiovascular markers.
Blood Pressure Outcomes and Risk Ratios
Children of mothers who smoked during pregnancy had statistically higher SBP and MAP compared to non-exposed peers.
The elevated blood pressure was present in both unadjusted and adjusted models, accounting for factors like BMI and socioeconomic status.
Children whose mothers smoked at any point had 1.44 times higher odds of hypertension by age 11–12 (95% CI: 1.01–2.06).
Among children exposed to high-intensity smoking (>10 cigarettes/day), SBP, DBP, and MAP were significantly elevated, indicating a dose-response effect (P-for-trend < .05).
Adjusted Odds and Cardiovascular Markers
Unadjusted models found that high-intensity prenatal exposure doubled the odds of hypertension (OR: 2.19; 95% CI: 1.37–3.49).
After full statistical adjustment, the odds remained high at 1.99 (95% CI: 1.22–3.24).
In absolute terms, children of mothers who smoked throughout pregnancy had:
- 2.54 mmHg higher systolic blood pressure
- 1.46 mmHg higher diastolic blood pressure
- 1.82 mmHg higher mean arterial pressure
This group also faced a 64% increased risk of meeting the clinical threshold for hypertension (OR: 1.64; 95% CI: 1.11–2.42).
Read also: High Blood Pressure During Pregnancy
No Significant Associations With PWV or cIMT
Unlike blood pressure, markers like pulse wave velocity (PWV) and carotid intima-media thickness (cIMT) did not show consistent associations with prenatal smoking exposure.
This suggests that elevated BP may be the earliest detectable cardiovascular alteration in children exposed to tobacco in utero.
Public Health Recommendations and Study Limitations
The authors urge population-level strategies to begin tobacco prevention before conception, not just during pregnancy.
Continued maternal health promotion is also necessary throughout pregnancy and into postpartum care.
Limitations include self-reported smoking status, which may underreport true exposure, and a study population that was predominantly White, which may reduce generalizability.
Still, the strength of the association, the clear dose-response trend, and the large sample size support the clinical relevance of these findings.
