On the short list of medical no-brainers is an obstetrician’s advice to a pregnant woman to stop smoking. It’s long been linked to premature birth, low birth weight, increased risk of miscarriage and other problems. But a first-ever study at UCHealth aims to shine light on what is now a medical black box: the effects of electronic (e-cigarette) use during pregnancy.
The recently launched three-site trial is funded by a five-year grant from the National Institutes of Health. It will compare levels of exposure to toxins, including nicotine, carbon monoxide and formaldehyde, and birth weights in three groups of pregnant patients: those who smoke cigarettes, those who inhale e-cigarette vapor, and those who do both. Researchers will collect blood and urine samples from the women during pregnancy as well as cord blood samples at delivery to measure toxin exposure, record birth weights, and follow mothers and their infants post-partum.
The times demand the study, said Beth Bailey, PhD, principal investigator for the trial at the Colorado site. Bailey is clinical research director of the Division of Maternal Fetal Medicine in the Department of Obstetrics and Gynecology at the University of Colorado School of Medicine. The negative effects on the fetus of cigarette smoking during pregnancy have been established for decades, she notes. By contrast, despite a recommendation from the Centers for Disease Control and Prevention that women avoid using them during pregnancy, e-cigarette manufacturers have flooded the market with some 460 brands without a thorough evaluation of their potential risks or benefits.
“We’d like to see reliable data on the potential dangers of using e-cigarettes during pregnancy,” Bailey said. “We hope the study will give us good data for clinicians to help them decide what they need to be doing to inform pregnant women.”
Vetting the vape
The study could also help establish as yet unsupported claims that the nicotine delivery devices are not only safer than conventional cigarettes – they heat liquid nicotine and convert it to a vapor that does not contain toxins like carbon monoxide and tar – but also could help some people stop smoking.
“There is a pervasive perception that they are safe,” Bailey said. “Our goal is always to help women stop smoking completely. But pregnancy is a stressful time. The question is what can we do to change behaviors? Can we recommend e-cigarettes as part of the process of discontinuing nicotine? We don’t have the evidence yet.”
Nor is there much evidence yet of the possible health effects on pregnancy of taking heated, nicotine-laden, flavored vapor into the lungs through e-cigarettes, noted Dr. Shane Reeves, associate professor of OB-GYN and Maternal Fetal Medicine with the CU School of Medicine. Reeves, who practices at UCHealth University of Colorado Hospital on the Anschutz Medical Campus, is a co-investigator for the study.
Reeves is keenly interested in understanding the factors that contribute to low infant birth weight. He said that women with lung disease generally are at higher risk of pregnancy problems like preeclampsia (dangerous increases in blood pressure) and preterm delivery. He wonders if the e-cigarette nicotine delivery system could cause lung inflammation, which in turn could contribute to the same kinds of health risks and poor outcomes for pregnant women and their infants.
“The delivery system itself needs to be studied because it is biologically plausible that it causes more problems than the nicotine itself,” Reeves said. “The other chemicals in the system – the flavors – could also be harmful. We don’t have any data on delivering a flavor during pregnancy that goes into the lungs as opposed to just the mouth.”
Studying the bad to do good
The study carries a bit of irony in that both Bailey and Reeves strongly encourage women who smoke to quit, if not altogether, at least during pregnancy. Bailey, for example, has studied the effects of prenatal tobacco exposure for many years, notably in northeast Tennessee, where she says close to one in three women smoke, contributing to high rates of premature birth and low birth weight infants.
“It’s a huge public health problem,” Bailey said. “Tobacco use, more than any other modifiable factor, contributes to poor pregnancy outcomes.”
Reeves is equally adamant. “The number-one thing to recommend to pregnant women is cessation of tobacco use,” he said. He noted that women who stop smoking by the end of the 16th week of pregnancy will generally have birth outcomes similar to those of non-smokers. Women who stop by the 28th week significantly reduce the risk of delivering a small baby, he added. These clinical recommendations are supported by population-based data Bailey presented earlier this year at the Society for Fetal Medicine annual scientific meeting.
Yet to get the data they want, the two researchers must find women who will continue to pursue the very activity they discourage. In addition, the study excludes women who use nicotine replacement therapies – patches and gum – to ensure consistent data.
“The study is of smokers,” Reeves acknowledged. “Some pregnant women refuse to quit, and they are the best and the most eligible for the study.”
It’s impossible to clear the air about the effects of e-cigarettes – good, bad or indifferent – in pregnant women without studying those who actually use them, Bailey agreed.
“We’d like to see reliable data on the potential dangers of using e-cigarettes during pregnancy,” she said. Without the information, she added, “We couldn’t counter the recommendation that they are safe to use, even if we suspect they aren’t.”
For more information about the “Electronic Cigarette Use during Pregnancy” trial, contact Beth Bailey, PhD, at 303-724-2909 or beth.bailey@ucdenver.edu.