Prenatal Exposure to Tobacco Q&A with Dr. Brianna Moore

Published: September 4, 2020

Dr. Brianna Moore is an environmental epidemiologist and Assistant Professor at the Michael & Susan Dell Center for Healthy Living. Dr. Moore completed her postdoctoral training in Epidemiology at the University of Colorado, Anschutz Medical Campus and a PhD in Environmental Health, specializing in Epidemiology, at Colorado State University. Her research examines how early-life exposure to environmental chemicals may contribute to childhood growth and neurodevelopment.

Earlier this year Dr. Moore and her team published the Prenatal Exposure to Tobacco and Offspring Neurocognitive Development in the Healthy Start Study in the Journal of Pediatrics. The researchers explored the associations between prenatal exposure to tobacco and neurocognitive development in the absence of prematurity or low birth weight. We reached out to Dr. Moore to have her answer some questions about the public health significance of her findings. Keep reading to learn more!

1. How did the study account for prenatal exposure to tobacco without prematurity or low birth weight?

It is well-known that smoking during pregnancy can contribute to pre-term delivery or low birth weight. These outcomes are often associated with developmental delays in early childhood. For this study, we excluded those who were born pre-term or low birth weight to see if prenatal exposure to tobacco, alone, contribute to developmental delays.

2. What advice do you have for families with mothers that continue smoking in the postpartum period?

First, I would encourage any woman to seek help to quit smoking. Quitting can be quite difficult in the postpartum period, so seeking professional help would be my first piece of advice. Second, I would encourage parents to limit their child’s exposure to tobacco. Some practical ways to do this might be to reduce the number of cigarettes smoked per day, smoke outside of the home (with the door shut), and/or to wear a “smoking jacket” that is taken off prior re-entering the home (to reduce thirdhand exposures). Finally, in the event that exposure to secondhand smoke cannot be avoided, it may be beneficial for children to eat a diet high in antioxidants and omega-3s to mitigate the effects of this exposure.

3. The hypothesis posed by the study has not been well covered in previous literature. How did you become interested in this particular subject? 

I have long been interested in how the timing of exposure to tobacco influences childhood health. Pregnancy is a crucial time for fetal brain development and most studies focus on this time period. The developing brain continues to be vulnerable to secondhand smoke in early childhood, but this topic is less-studied. In this study, we wanted to focus on prenatal exposure to tobacco while also attempting to separate the effects of postnatal exposure to secondhand smoke.

4. Why did your team decided to expand the Healthy Start study to explore how exposures in early life influence childhood growth and development?

Dr. Dana Dabelea, Professor of Epidemiology and Pediatrics and Director of the Lifecourse Epidemiology of Adiposity and Diabetes Center at the Colorado School of Public Health, established Healthy Start to follow a cohort of pregnant women and their offspring to explore whether fetal over-nutrition is associated with obesity and other metabolic disorders in the offspring. Due to its thorough collection of maternal and childhood characteristics, Healthy Start has been expanded to assess a range of exposure-outcome relationships. It is quite impressive the amount of data that is being collected, especially as Healthy Start is now a part of the ECHO consortium from the National Institutes of Health. For my research, I have focused on the impact of prenatal and postnatal exposures to secondhand smoke on childhood health outcomes.

5. What public health interventions would you consider effective to address the higher exposure to tobacco during pregnancy in young mothers?

There are two potential strategies. The first strategy might be to educate young, pregnant women about the benefits of smoking cessation for themselves and for their offspring. Another strategy may be to prevent smoking initiation or encourage smoking cessation prior to pregnancy. Many interventions begin in childhood and adolescence, which may be an ideal time to intervene.

6. Do you have any theories as to why only 25% of the women exposed to tobacco during pregnancy breastfed their infants longer than 5 months?

This might be due to a clustering of risk factors among those who smoke or live with smokers, such as residing in multi-unit housing or having lower educational attainment. Interestingly, a potential strategy for preventing smoking relapse in the postpartum period is to encourage breastfeeding. So, it might be beneficial to educate expecting mothers to quit smoking while also encouraging them to breastfeed, in order to achieve the maximum public health benefit.

7. The Healthy Start study found that compared with non-exposed offspring, exposed offspring had 3.9 times the odds of fail/monitor score for the fine motor skills. What does this mean in the long-term?

Compared to children with no exposure, children who were exposed to tobacco in pregnancy were 3.9 times more likely to experience lagging fine motor skills, which includes drawing, writing, or cutting a piece of paper. This means that these children may need to be monitored or helped to establish these important classroom skills needed for elementary school.

8. The discussion section of the study explains: "The findings suggest that pregnancy may be the most susceptible developmental period for offspring motor development, whereas postnatal exposures continue to influence offspring cognitive development." Why is this differentiation important? What benefits could this knowledge bring to children's early brain development?

Understanding when exposure to tobacco influences childhood neurodevelopment is important for helping us to figure out how this happens. Once it is more clear when and how this happens, we can hopefully identify potential interventions to mitigate the effects of tobacco on the developing brain.