Association between preconception paternal smoking and birth defects in offspring: evidence from the database of the National Free Preconception Health Examination Project in China

Abstract

Objective: To clarify whether preconception paternal smoking has any adverse effects on the offspring.

Design: Prospective, population-based study.

Setting: Preconception registry data from the National Free Preconception Health Examination Project.

Population or sample: Couples planning pregnancy, with complete information on preconception paternal smoking behaviour and pregnancy outcomes.

Methods: The effect of questionnaire-based paternal smoking behaviour during preconception and pregnancy was assessed via logistic regression. Additionally, we performed a 1:1 case-control (birth defects versus normal pregnancy) analysis, matched for maternal province, folic acid supplementation and paternal alcohol consumption.

Main outcome measures: Risk of birth defects in offspring.

Results: In total, 566 439 couples with complete information on preconception paternal smoking behaviour and pregnancy outcomes were enrolled. The preconception paternal smoking rate was 28.7% (162 482) overall: 8.7% (49 303) stopped smoking, 13.3% (75 517) decreased their smoking, and 6.6% (37 662) continued smoking during early pregnancy. The risk of birth defects was higher in the continued-smoking (P < .000, odds ratio [OR] 1.87, 95% CI 1.36-2.56) and decreased-smoking groups (P = .007, OR 1.41, 95% CI 1.10-1.82). In the case-control analysis, infants whose fathers stopped (P = .003, OR 0.32, 95% CI 0.15-0.67) or decreased smoking (P = .000, OR 0.25, 95% CI 0.13-0.49) were at lower risk of congenital heart diseases, limb abnormalities, digestive tract anomalies and neural tube defects than those whose fathers continued smoking.

Conclusion: Preconception paternal smoking may be associated with congenital heart diseases, limb abnormalities and neural tube defects in the offspring. Changes in smoking behaviour may reduce this risk.

Tweetable abstract: This study suggests that preconception paternal smoking is associated with birth defects in offspring. Changes in smoking behaviour may reduce this risk.

Keywords: Birth defects; China; preconception paternal smoking.