Smoked, smokeless, and poly-tobacco use during pregnancy in relation to infant mortality in Cambodia: Findings from a nationwide sample.

Introduction: Maternal cigarette smoking during pregnancy is an established risk factor for adverse maternal, fetal, and infant outcomes. In contrast, maternal smokeless tobacco use (i.e. e-cigarettes, snus, betel quid, iqmik) during pregnancy has a more complex risk profile due to its potential use as a smoking cessation aid or to reduce the harm from smoking tobacco. The overall aim of this study was to investigate the association between smoked, smokeless, and poly-tobacco (smoked + smokeless) use during pregnancy and infant mortality, in a national sample of women in Cambodia.

Methods: The study used data from the National Adult Tobacco Survey of Cambodia (NATSC) that employed sampling methods and tobacco survey items from the CDC Global Adult Tobacco Survey but also included a supplement on reproductive health and birthing history. We selected 5342 women of the NATSC who reported complete data on at least one pregnancy, and our unit of analysis was the 15998 pregnancies from these women. We conducted a multivariable logistic regression to relate tobacco use to infant mortality. Taylor linearized variance estimators were used to account for clustering by sampling unit and mother.

Results: We found that smokeless tobacco in the form of a betel quid was the most common form of tobacco used during pregnancy. In multivariable logistic regression, we found increased odds of infant death for all tobacco use categories (smoked, smokeless), but that the strongest effects were seen for habits that included smokeless tobacco (relative to never use of tobacco in any form): exclusive use of smokeless tobacco (adjusted odds ratio, AOR=2.08; 95% CI: 1.15-3.76), and poly-tobacco use (AOR=5.68; 95% CI: 1.03-31.46). In more detailed analyses that considered the composition of the betel quid (tobacco, areca nut/leaf, slaked lime), we found that even chewing of tobacco leaves with no processing or additives was associated with a three-fold increase in odds of infant death relative to a never user (AOR=3.05; 95% CI: 1.45-6.45).

Conclusions: We found that even among those pregnant women who limited their nicotine habit to chewing tobacco leaves with no processing or additives, there remained higher odds of fetal or infant death from that pregnancy.