Does Maternal Smoking Increase the Risk of Congenital Heart Disease? Insights from a Single-Center Fetal...

Background: Congenital heart disease (CHD) represents a major cause of perinatal morbidity and mortality, and fetal echocardiography is essential for its early diagnosis and management. Maternal smoking has been suggested as a potential teratogenic factor affecting fetal cardiovascular development; however, findings regarding its association with CHD remain inconsistent. This study aimed to evaluate the relationship between maternal smoking during pregnancy and the risk of CHD. Methods: A total of 2715 pregnant women and 2784 fetuses who underwent fetal echocardiography at ≥20 weeks' gestation between 1 January 2024 and 1 November 2025 were analyzed. Pregnancies complicated by known chromosomal or syndromic abnormalities, significant teratogenic exposure, duplicate assessments, or nonstandard examinations were excluded. Maternal smoking status during pregnancy was recorded and categorized according to daily cigarette consumption. The prevalence of CHD and the distribution of CHD subtypes were evaluated and compared according to smoking status. Fetal cardiac diagnoses were classified based on the classical morphological classification system. Results: A total of 2715 pregnancies (2784 fetuses) were analyzed, including 2530 fetuses in the non-smoking group and 254 in the smoking group. Congenital heart disease was detected in 12.5% of fetuses in the non-smoking group and 14.2% in the smoking group, with no statistically significant difference (p = 0.442). According to the classical morphological classification, the distribution of fetal echocardiographic pathologies did not differ significantly between groups (p = 0.607). Septal defects were the most common subtype in both groups. Although conotruncal defects were proportionally more frequent in the smoking group, this difference did not reach statistical significance. After reclassifying daily cigarette consumption into four exposure categories, no association was detected between maternal smoking and CHD risk (OR = 1.04; 95% CI: 0.86-1.26; p = 0.691). Conclusion: In this cohort referred for fetal echocardiographic evaluation, no association was detected between maternal smoking during pregnancy and the risk of congenital heart disease or alterations in CHD subtype distribution. No consistent dose-response relationship was observed. These findings suggest that no association was detected between maternal smoking exposure and CHD. Further large-scale prospective studies are needed to clarify phenotype-specific associations.