Beth Bailey, PhD; Judy McCook, PhD, RN; Alexis Hodge, BSN; Andrea Clements, PhD; Lana McGrady, MS

INFANT BIRTH OUTCOMES INFANT BIRTH OUTCOMES AMONG SUBSTANCE USING AMONG SUBSTANCE USING

WOMEN: WOMEN: WHY QUITTING SMOKING IS WHY QUITTING SMOKING IS

JUST AS IMPORTANT AS JUST AS IMPORTANT AS QUITTING HARDER DRUGSQUITTING HARDER DRUGSBeth 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

BACKGROUBACKGROUNDND 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

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

BACKGROUBACKGROUNDND

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

BACKGROUBACKGROUNDND

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 resources5

BACKGROUBACKGROUNDND

STUDY STUDY OBJECTIVEOBJECTIVE

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

METHODSMETHODS

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

Birth Weight (gm)

Gestational Age (wk)

No Cig/No Drug 3232 38.9Cigarette Only 3068 38.7Illicit Drug Only 3054 38.1Cig AND Drug 2954 38.5F, p 3.70, p=.012 .89, p=.447

Substance Use Group Differences on Primary Birth Outcomes

RESULTSRESULTS

Effect for birth weight remained significant after control for significant confounders (education, preeclampsia, race): F=4.55, p=.004

RESULTSRESULTS

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

RESULTSRESULTS

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

RESULTSRESULTS

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

CONCLUSIONSCONCLUSIONS

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

CONCLUSIONSCONCLUSIONS

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

CONCLUSIONSCONCLUSIONS

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

CONCLUSIONSCONCLUSIONS

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

INFANT BIRTH OUTCOMES INFANT BIRTH OUTCOMES AMONG SUBSTANCE USING AMONG SUBSTANCE USING

WOMEN: WOMEN: WHY QUITTING SMOKING IS WHY QUITTING SMOKING IS

JUST AS IMPORTANT AS JUST AS IMPORTANT AS QUITTING HARDER DRUGSQUITTING HARDER DRUGSBeth 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