1. INFANT BIRTH OUTCOMES AMONG SUBSTANCE USING WOMEN: WHY QUITTING SMOKING IS JUST AS IMPORTANT AS QUITTING HARDER DRUGS Beth Bailey, PhD; Judy McCook, PhD, RN; Alexis Hodge, BSN; Andrea Clements, PhD; Lana McGrady, MS Departments of Family Medicine and Psychology, and the College of Nursing, East Tennessee State University

2. BACKGROUND  Significant intervention resources have necessarily and successfully been devoted to helping substance using pregnant women become drug free  Unfortunately, the vast majority of pregnant women who successfully quit using illicit drugs continue to smoke  Health professionals often prioritize cessation of illicit drug use over the elimination of smoking during pregnancy  Reasons cited include the belief that illicit drug use is more harmful to the fetus than smoke exposure and the need to save limited time available to focus on that drug use and other negative health behaviors 2

3.  A substantial body of research has examined the link between pregnancy substance use and birth outcomes  Evidence supports an association between pregnancy alcohol use and preterm and low birth weight delivery  Evidence is mixed for the link between pregnancy opiate use, benzodiazepine use, and birth outcomes; effects often minimal when control for confounding factors  Evidence is also mixed for the link between stimulant use (i.e. methamphetamine) and birth outcomes  No significant evidence for link between marijuana use and birth outcomes 3 BACKGROUND

4.  Link between pregnancy smoking and birth outcomes has also been well studied  At this point evidence is unequivocal – strong support for a causal association between exposure and poor birth outcomes  Babies born to smokers are up to 300 gm lighter and half an inch shorter  Preterm delivery has also been noted in some studies, but significant evidence that size effects are due primarily to intrauterine growth restriction rather than preterm delivery 4 BACKGROUND

5.  Due to the magnitude of effects of prenatal cigarette exposure and the relative prevalence, a recent population-based study found that the elimination of smoking would have a much greater impact on decreasing poor birth outcomes than elimination of any other substance  However, few studies have quantified the relative impact on birth outcomes of different prenatal exposures  Such knowledge is important in order to prioritize limited pregnancy intervention resources 5 BACKGROUND

6. STUDY OBJECTIVE The goal of the current study was to examine the impact of pregnancy tobacco use, relative to the use of illicit drugs, on birth outcomes. 6

7. METHODS 7  Women were recruited at entry to prenatal care at multiple medical practices in NE TN  Background and substance use information was collected via interviews, medical chart review, and UDS during pregnancy  Final sample was restricted to infants who had biological testing for substances at delivery (i.e. meconium), which oversampled substance users  Final sample contained 265 infants:  No cigarette/no drug use (n=46)  Cigarette use only (n=75)  Illicit drug use only (n=21)  Cigarette & illicit drug use (n=123)

8. 8 Birth Weight (gm) Gestational Age (wk) No Cig/No Drug 323238.9 Cigarette Only 306838.7 Illicit Drug Only 305438.1 Cig AND Drug 295438.5 F, p 3.70, p=.012.89, p=.447 Substance Use Group Differences on Primary Birth Outcomes RESULTS Effect for birth weight remained significant after control for significant confounders (education, preeclampsia, race): F=4.55, p=.004

9. RESULTS 9 Adjusted Birth Weights for the 198 Smokers:  Smoked Only (n=75) 3065 gm  Smoked AND Used Marijuana (n=39)3068 gm  Smokes AND Hard Illicit Drug Use (n=84)2902 gm  Test for group difference: F=3.39, p=.036  Adjusted Birth Weight Difference = 163 gm  Interpretation: Compared with those who both smoked and used hard illicit drugs, those who smoked but DID NOT USE HARD ILLICIT DRUGS had a 163gm gain in adjusted birth weight – a 5.6% improvement. Effect of Illicit Drug Use on Birth Weight

10. RESULTS 10 Adjusted Birth Weights for the 105 Hard Illicit Drug Users:  Hard Drug Use Only (n=21) 3207 gm  Hard Drug Use AND Smoked (n=84)2890 gm  Test for group difference: F=6.28, p=.014  Adjusted Birth Weight Difference = 317gm  Interpretation: Compared with those who both smoked and used hard illicit drugs, those who used hard illicit drugs BUT DID NOT SMOKE had a 317 gm gain in adjusted birth weight – an 11.0% improvement. Effect of Smoking on Birth Weight

11. RESULTS 11 Adjusted Birth Weights:  No smoking/No Drug Use (n=46)3248 gm  Smoked AND Hard Drug Use (n=84)2896 gm  Test for group difference: F=17.42, p<.001  Adjusted Birth Weight Difference = 352gm  Interpretation: Compared with those who both smoked and used hard illicit drugs, those who USED NEITHER SUBSTANCE had a 352 gm gain in adjusted birth weight – a 12.2% improvement. Effect of BOTH Smoking AND Hard lllicit Drug Use on Birth Weight

12. CONCLUSIONS 12  Pregnancy substance use was NOT associated with early delivery in the current sample  This finding is consistent with many previous studies  This suggests that links found between pregnancy substance use and birth weight are a result of the effects of substances on prenatal growth, rather than a result of shortened gestation Substance Use and Gestational Age

13. CONCLUSIONS 13  Pregnancy marijuana use did not adversely impact birth weight BEYOND the effects of cigarette smoking  Could not tell from current study the impact of marijuana use on birth weight in the absence of cigarette use  This finding is consistent with many previous studies  This finding suggests that for pregnant women who both smoke and use marijuana, quitting marijuana use while continuing to smoke will not lead to improved birth outcomes Pregnancy Marijuana Use

14. CONCLUSIONS 14  The current study demonstrated that pregnancy smoking had twice the impact on birth weight as illicit drug use  Findings support the assertions of those who have suggested that pregnancy smoking may be even more detrimental to the developing fetus than the use of any illicit drugs  Findings also support the need to direct more attention toward increasing pregnancy smoking cessation efforts  Pregnant women should be strongly advised of the risks of continued smoking, and should be assisted in their efforts to eliminate the use of ALL substances, including tobacco Hard Illicit Drug Use Vs. Smoking in Pregnancy

15. CONCLUSIONS 15  Possible misclassification of substance use  With the exception of marijuana, unable to separately examine the impact of different illicit substances on birth outcomes, or the impact of alcohol use  Representativeness of current sample  Did not look at longer term impact of exposures – on child health or development; testing of the current sample at 15 months of age is underway – have seen health and developmental effects related to smoking specifically Study Limitations

16. INFANT BIRTH OUTCOMES AMONG SUBSTANCE USING WOMEN: WHY QUITTING SMOKING IS JUST AS IMPORTANT AS QUITTING HARDER DRUGS Beth Bailey, PhD; Judy McCook, PhD, RN; Alexis Hodge, BSN; Andrea Clements, PhD; Lana McGrady, MS Accepted for Publication (2/2011): Maternal and Child Health Journal