Date of Award

January 2012

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Kimberly A. Yonkers

Subject Area(s)

Medicine

Abstract

PRENATAL HAZARDOUS SUBSTANCE USE AND ADVERSE INFANT BIRTH OUTCOMES.

Odayme Quesada, Nathan Gotman, Kimberly A. Yonkers (Sponsored by Doris Duke Charitable Foundation). Department of Psychiatry, Yale University, School of Medicine, New Haven, CT.

This thesis is composed of two studies, which assessed the effect of prenatal substance use on infant birth outcomes. The first study systematically analyzed a full spectrum of hazardous substance and known risk factors to determine which has a greater effect on infant birth outcomes. We used data from two comprehensive, prospective cohort studies and recursive partitioning class analysis to characterize the effect of in utero hazardous substance exposure on preterm birth and delivering a small for gestational age infant. Compared to cocaine and opiate non-users, cocaine users were 3.53 times as likely (95% CI: 1.65-7.56; p=0.001) and opiate users 2.86 times as likely (95% CI: 1.11-7.36; p=0.03) to deliver preterm. The odds of delivering a small for gestational age infant for women who smoked more than two cigarettes daily was 3.74, (95% CI: 2.47-5.65; p<0.0001) compared to women who smoked two or less cigarettes daily and had one previous child. Similarly, less educated, nulliparous women who smoked two or fewer cigarettes daily were 4.12 times as likely (95% CI: 2.04-8.34; p<0.0001) to have a small for gestational age infant. In conclusion, among our covariates, prenatal cocaine and opiate use are the predominant risk factors for preterm birth; while tobacco use was the primary risk factor predicting small for gestational age at delivery. Multi-substance use did not substantially increase risk of adverse birth outcomes over these risk factors.

Our second study focused on the effects of timing and amount of exposure on birth outcomes. Despite our desire to look at these effects for different substances individually our sample size only allowed us to do so for marijuana and tobacco. To explore effects, we used prospectively collected biological and self report data from participants enrolled in an integrated obstetrical/substance abuse treatment program. In our cohort prenatal marijuana use appeared to affect infant head circumference. There was no clear association between marijuana use and other growth parameters, gestational age, or ponderal index. Nor was there a clear association between cigarette use and any of the infant birth outcomes assessed. In conclusion, marijuana use appeared to affect growth parameters, thus implying some effect on growth retardation.

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