Online Program

Maternal Smoking by Trimester of Pregnancy and Risk of Small-for-Gestational-Age

Wednesday, November 4, 2015

Sabrina Luke, Department of Community and Family Health, University of South Florida, Tampa, FL
Russell Kirby, PhD, Maternal and Child Health, University of South Florida, Tampa, FL
Background: Infants born small-for-gestational-age (SGA) are at increased risk for severe disabilities and chronic health problems. Smoking and hypertension during pregnancy pose some of the most significant risk factors for fetal growth restriction. The aims of this study are to identify 1) whether the timing and dosage of maternal tobacco use modifies the risk of SGA, 2) whether there are differences in association by percentile of SGA (3rd, 5th and 10th percentile), and 3) whether the effect of tobacco exposure on SGA outcome is mediated by the presence of hypertension.  

Methods: Data were obtained from the 2009 Natality public use file available through National Center for Health Statistics. Multivariable log-linear regression models were performed to determine the association between percentile of SGA outcome (3rd, 5th and 10th) and trimester and dosage of tobacco exposure.

Results: Hypertension and smoking appeared to work synergistically to restrict fetal growth. Women who smoked moderately in all three trimesters and had hypertension were 4.34 times more likely to give birth to a 3rd percentile SGA infant compared to non-smoking normotensive women. However, the effect of hypertension was protective for giving birth to a 10th percentile SGA infant among women who smoked moderately across all three trimesters.

Conclusions: The timing and duration of tobacco exposures mediate the risk and severity of fetal growth restriction. This relationship was modified by presence of hypertension which may indicate different etiologies between pathologically growth restricted infants and constitutionally growth restricted infants.

Learning Areas:

Public health or related research

Learning Objectives:
Identify the effect of tobacco exposure on small-for-gestational infants (SGA). Compare birth outcomes by trimester of tobacco exposure. Analyze the role of hypertension in modifying the effect of tobacco. Demonstrate that there are differences in outcome by percentile SGA.

Keyword(s): Tobacco Use, Perinatal Health

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have co-authored numerous publications in the area of perinatal epidemiology. I hold a masters in public health specializing in epidemiology and I am currently pursuing a doctoral degree with an emphasis in maternal and child health.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.