Background: Electronic cigarettes (e-cigarettes) function by aerosolizing a base liquid containing nicotine and flavoring, used by an estimated 15% of pregnant women as a supposed safer alternative to traditional cigarettes. Our previous studies demonstrated e-cigarettes can delay gestation. Limited studies have examined in vivo effects on the placenta.
Methods: We exposed adult pregnant C57BL/6J female mice to flavored e-cigarettes with and without nicotine (VAPE NIC & VAPE). We measured implantation success (N = 10 SHAM, N = 17 VAPE, N = 13 VAPE NIC), erythrocyte presence (N = 29 SHAM, N = 29 VAPE, N = 26 VAPE NIC) and embryo elongation (N = 25 SHAM, N = 29 VAPE, N = 22 VAPE NIC) per implant site at day 6.5 at 13-21 weeks of age. Fetal and placental weight (N = 11 SHAM, N = 14 VAPE, N = 12 VAPE NIC) was evaluated at day 12.5 in mice aged 15-39 weeks, while placental gene expression was separately analyzed by offspring sex (N = 7 total, N = 3 sex-specific).
Results: Here we show that e-cigarettes cause similar embryo elongation and in the absence of nicotine, exhibit elevated implant site blood cell accumulation which may contribute to fetal demise. With nicotine, e-cigarettes elicit a reduction in embryo to placental weight ratios. Genes involved in hypoxia, reactive oxygen species response, and placental growth including hypoxia inducible factor 1, alpha subunit (Hif1a), prostaglandin-endoperoxide synthase 2 (Ptgs2), glutathione peroxidase family members 2 and 3 (Gpx2/Gpx3), thioredoxin reductase 1 (Txnrd1), and mitogen-activated protein kinase 1 (Mapk1) exhibit marked decreases in placental tissue depending on fetal sex and nicotine presence.
Conclusions: Our findings conclude flavored e-cigarettes modulate in vivo implantation and placentation mechanisms depending on the presence of nicotine. This work presents a measure of concern for flavored e-cigarette use during pregnancy.
Maternal smoking results in numerous adverse pregnancy outcomes. To avoid these dangers, women have started using electronic cigarettes or e-cigarettes as a perceived safer alternative. However, the safety of e-cigarette use during pregnancy is unknown. E-cigarettes heat an inhaled liquid containing glycerol, flavoring, and nicotine. Recent findings have determined e-cigarettes can impact early pregnancy. However, these studies are limited. Here we exposed mice to e-cigarette vapors containing flavoring with and without nicotine. We determined nicotine can impair fetal and placental growth, while the absence of nicotine may cause early miscarriage. Finally, we determined that several placental genes were changed depending on the presence of nicotine and fetal sex. Thus, we conclude e-cigarettes cause negative effects on pregnancy and should not be used.
© 2025. The Author(s).