Holme Jørn A, Valen Håkon, Brinchmann Bendik C, Vist Gunn E, Grimsrud Tom K, Becher Rune, Holme Ane M, Øvrevik Johan, Alexander Jan
Division of Climate and Health, Norwegian Institute of Public Health, Oslo, Norway.
Division of Climate and Health, Norwegian Institute of Public Health, Oslo, Norway; Department of Occupational Medicine and Epidemiology, National Institute of Occupational Health, Oslo, Norway.
Toxicology. 2022 May 15;473:153206. doi: 10.1016/j.tox.2022.153206. Epub 2022 May 10.
Tobacco smoking and use of snus (smokeless tobacco) are associated with adverse effects on pregnancy and neonatal outcomes. Nicotine is considered a key toxicant involved in effects caused by both smoking and snus, while pyrolysis products including polycyclic aromatic hydrocarbons (PAHs) in cigarette smoke represents the constituents most unequally divided between these two groups of tobacco products. The aim of this review was: i) to compare the impact, in terms of relative effect estimates, of cigarette smoking and use of Swedish snus on pregnancy outcomes using similar non-tobacco user controls, and ii) to examine whether exposure to PAHs from smoking could explain possible differences in impact on pregnancy outcomes. We systematically searched MEDLINE, Embase, PsycInfo, Web of Science and the Cochrane Database of Systematic Reviews up to October 2021 and identified studies reporting risks for adverse pregnancy and neonatal outcomes associated with snus use and with smoking relative to pregnant women with no use of tobacco. Both snus use and smoking were associated with increased risk of stillbirth, preterm birth, and oral cleft malformation, with comparable point estimates. These effects were likely due to comparable nicotine exposure. We also found striking differences. While both smoking and snus increased the risk of having small for gestational age (SGA) infants, risk from maternal smoking was markedly higher as was the reduction in birthweight. In contrast, the risk of preeclampsia (PE) was markedly lower in smokers than in controls, while snus use was associated with a slightly increased risk. We suggest that PAHs acting via AhR may explain the stronger effects of tobacco smoking on SGA and also to the apparent protective effect of cigarette smoking on PE. Possible mechanisms involved include: i) disrupted endocrine control of fetal development as well as placental development and function, and ii) stress adaption and immune suppression in placenta and mother.
吸烟和使用口含烟（无烟烟草）会对妊娠和新生儿结局产生不良影响。尼古丁被认为是吸烟和口含烟所造成影响的关键有毒物质，而香烟烟雾中的热解产物，包括多环芳烃（PAHs），是这两类烟草制品中分布最不均衡的成分。本综述的目的是：i）使用相似的非烟草使用者对照，比较吸烟和使用瑞典口含烟对妊娠结局的影响（以相对效应估计值衡量）；ii）研究吸烟导致的多环芳烃暴露是否能够解释对妊娠结局影响的可能差异。我们系统检索了截至2021年10月的MEDLINE、Embase、PsycInfo、Web of Science和Cochrane系统评价数据库，并确定了报告与使用口含烟和吸烟相关的不良妊娠和新生儿结局风险的研究，这些研究以未使用烟草的孕妇作为对照。使用口含烟和吸烟均与死产、早产和口腔腭裂畸形风险增加相关，点估计值相当。这些影响可能是由于相当的尼古丁暴露。我们也发现了显著差异。虽然吸烟和使用口含烟都会增加小于胎龄（SGA）婴儿的风险，但母亲吸烟导致的风险明显更高，出生体重降低的情况也是如此。相比之下，吸烟者患先兆子痫（PE）的风险明显低于对照组，而使用口含烟则与风险略有增加相关。我们认为，通过芳烃受体（AhR）起作用的多环芳烃可能解释了吸烟对小于胎龄儿的更强影响，以及吸烟对先兆子痫的明显保护作用。涉及的可能机制包括：i）胎儿发育以及胎盘发育和功能的内分泌控制受到干扰；ii）胎盘和母亲的应激适应和免疫抑制。
