Association of E-Cigarette Use during Pregnancy with Adverse Birth Outcomes: A Meta-Analysis

- With the increasing growth of the global e-cigarette market, more and more pregnant women use e-cigarettes as a safe alternative to traditional cigarettes. However, several studies have shown that e-cigarettes damage the human respiratory and cardiovascular systems and that nicotine is a risk factor for fetal development. To determine the association between e-cigarette use during pregnancy and adverse birth outcomes in pregnant women, we conducted a meta-analysis to assess the present evidence's strength. 735 studies were screened through PubMed, Web of Science, and Scopus databases. A total of nine articles met the inclusion criteria of this paper, and six articles were conducted for a meta-analysis after excluding studies with high heterogeneity. The six studies were further divided into two subgroups based on their differences in study types and population samples: one subgroup was three national case-control studies based on the United State Pregnancy Risk Assessment Monitoring System (PRAMS) database, and the other included three small-scale regional studies. The small for gestational age (SGA) was identified as the indicator for assessing the association between e-cigarette use and adverse birth outcomes in pregnant women. We found a significant association of pregnant women using e-cigarettes during pregnancy with SGA (OR = 1.32, 95%CI = 1.03, 1.69). Low heterogeneity of multiple studies (I 2 =32%) and low publication bias as indicated by funnel plots. Our research proves that the risks of e-cigarette use during pregnancy to the unborn child are evident. Therefore, pregnant women need to be advocated to reduce their use of e-cigarettes during pregnancy.