A new study published in JAMA Network Open examines fetal health outcomes in babies born to teenagers who smoked, vaped, or did both.
Study: Use of E-cigarettes and cigarettes during late pregnancy among adolescents. Image Credit: Africa Studio / Shutterstock.com
Nicotine use during pregnancy
In 2021, statistics indicated that over 4% of pregnant adolescents used cigarettes as compared to 6% among young women between 20 and 24 years of age. Corresponding data is scarce on vaping during pregnancy among adolescents; however, 14% of high school students reported using e-cigarettes in 2022.
Cigarettes produce a wide range of toxins, including carbon monoxide, nicotine, and several tars. Vaping avoids the emission of many of these chemicals and, as a result, has been reported to be used during pregnancy as a healthier option or to help smokers quit. However, nicotine delivery is comparable for both forms of smoking, though other toxins are reduced by one to two orders of magnitude.
Despite this reduction, the presence of these toxins could contribute to the adverse outcomes associated with vaping in pregnancy, such as small babies and premature births. Babies who are small for gestational age (SGA) weigh below the 10th percentile for gestational age at birth. These babies are at an increased risk of poor long-term outcomes such as stunted growth, impaired neurodevelopment, and type 2 diabetes.
Earlier research indicated a greater reduction in birth weight among babies born to teenagers who smoked as compared to adults who smoked during pregnancy, as well as a three-fold increase in SGA risk among smoking pregnant teenagers as compared to those who did not smoke. However, not much is known about how vaping affects birth weight in this age group.
About the study
The current study explored data collected from the Pregnancy Risk Assessment Monitoring System between 2016 and 2017. Data from over 10,000 American teenagers who gave birth to singleton children and whose records provided complete information on their use of smoking or vapes, as well as birth weight, were analyzed.
The study aimed to determine whether babies born to adolescents who used either or both e-cigarettes and vapes were more likely to be SGA as compared to babies of non-smoking, non-vaping teenage mothers.
What did the study show?
The study included about 10,400 pregnant teens, about 75% of whom were between 18 and 19 years of age. About 60% of the mothers in this study were White, 25% were Black, and 12% were Hispanic.
About 7% and 1.5% of the mothers in this study used cigarettes only and vapes only, respectively, with 1.2% using both. Over 90% did not smoke or vape during the last trimester. Among those who vaped, over 33% did so up to one day a week, whereas about 30% used vapes one or more times every day.
Exclusive cigarette smokers smoked between one and five cigarettes every day in half the cases, with over 20% smoking between six and ten cigarettes every day.
In 2021, vaping was the most prevalent form of smoking among pregnant teens at 4% as compared to 3% for cigarette use. The number of vape-alone users rose fivefold from 2016 to 2021, from eight of every 1,000 pregnant adolescents to 40. Moreover, cigarette-only smokers decreased during the same period from 92 per 1,000 in 2017 to 32.
The risk for vaping among pregnant adolescents was highest among White pregnant adolescents as compared to all other races, who were at nearly three times the usage rate. Adolescents of Alaska Native, American Indian, Asian, and other non-Black races also vaped more than those of other ethnicities.
Whites were most likely to smoke only e-cigarettes or cigarettes at 2.7% and 10%, respectively. The lowest vaping and cigarette smoking rates were reported among Blacks and Asians/other races, respectively.
Non-Hispanics were at a two-fold and almost five-fold greater risk for e-cigarette-only and cigarette-only use as compared to 1% and 2% prevalence among Hispanics, respectively.
About 14% of babies born in the sample were SGA. The prevalence of SGA babies was higher if they were born to mothers who were unmarried and had a lower body mass index (BMI) before pregnancy.
No significant association of either vaping alone or vaping in addition to cigarette use was observed with SGA. However, cigarette use in isolation was associated with a two-fold more significant risk of small babies, even after adjusting for confounding factors.
These findings corroborate those of earlier studies showing that cigarette smoking in pregnancy more than doubles the risk of SGA. This could be due to fetal hypoxia caused by exposure to carbon monoxide, which is not produced from e-cigarettes.
Previous studies have also reported vaping to be a risk factor for SGA birth among adolescents and adults; however, the current study findings did not corroborate this observation. One explanation for this difference may be the short period of usage of vapes, as the sample comprised middle and high school students, which may have led to lower exposure and reduced adverse effects.
The sample size may have been too low to detect these types of associations in the current study. Furthermore, it was not possible to differentiate between those who smoked either form throughout pregnancy as compared to those who did so only in late pregnancy.
Importantly, the researchers could not control for the abuse of other substances like cannabis, which is associated with fetal growth restriction and might mediate a significant amount of the association of SGA with low birth weight. There was no detailed classification of smokers by frequency of use; however, this could be related to growth outcomes in the fetus.
What are the implications?
The study findings suggest that a shift is occurring among pregnant adolescents from cigarettes to vapes, especially among Whites. While e-cigarette use increased, vaping prevalence decreased.
The shift is apparently beneficial in terms of birth weight, with vapes not being demonstrably associated with a higher risk of SGA. However, more extensive studies are needed to confirm this finding.