Date of Graduation


Document Type


Degree Type



School of Public Health



Committee Chair

Lesley Cottrell

Committee Co-Chair

Kim E Innes

Committee Member

Kim E Innes

Committee Member

Amna Umer

Committee Member

Tomi Marie Rudisill

Committee Member

Wei Fang


Background: In the United States, unintended pregnancy is a serious public health issue due to its persistent high prevalence. In the series of three studies, our first two investigations examined the risk and potential determinants of unintended pregnancy among substance and polysubstance using women of childbearing age. In the third study, we conducted a systematic review (SR) with meta-analysis (MA) to assess the association of illicit and recreational drugs to the risk of unintended pregnancy.

Methods: We performed a secondary data analysis on a subset of Pregnancy Risk Assessment Monitoring System (PRAMS) 2016-17 phase 8 data (n=75,543). The outcome variable was pregnancy intention. The exposure variable was substance use, including alcohol, cannabis, nicotine/tobacco, illicit/recreational drugs, and special medications, including prescription opioids, over-the-counter pain relief, and antidepressants. In the second study, the exposure variable was the use of alcohol in concert with other substances. We also evaluated the relation of specific sociodemographic and economic variables to the risk of unintended pregnancy. Data were analyzed using complex survey analysis. For the SR with MA, predetermined criteria were used to ascertain study eligibility. To identify eligible original studies for the full review, we screened abstracts from six electronic databases (PubMed (MEDLINE), Scopus, CINAHL, PsychINFO, and Web of Science) and citation indices from retrieved articles and recent reviews. The inverse variance method was used to calculate the pooled effect size.

Results: Overall, 41% of pregnancies were unintended. Approximately 57% of participants reported alcohol consumption, 17% reported smoking, and 10% cannabis use prior to conception. Study 1: Likelihood of unintended pregnancy was significantly associated with substance use, including cigarettes (Adjusted Odds Ratio (AOR):1.5, 95% CI: 1.4-1.6); use of other nicotine/tobacco products (AOR:1.4, 95% CI: 1.3-1.5); cannabis (AOR: 1.9, 95% CI: 1.5-2.3); illicit/recreational drugs (AOR:1.7, 95% CI: 1.2-2.4), prescription opioids (AOR:1.4, 95% CI: 1.02-1.9), and prescription antidepressants (AOR 1.8, 95% CI: 1.1-3.0). Among substance users, factors significantly associated with unintended pregnancy included maternal age <17, living in urban areas, lower educational attainment, annual income Study 2: The likelihood of unintended pregnancy was significantly elevated in those reporting co-use of alcohol with cigarette smoking (AOR: 1.5, 95%CI:1.4 – 1.6), cannabis (AOR: 2.0, 95%CI:1.6 – 2.4), tobacco/nicotine (AOR: 1.6, 95%CI:1.4 – 1.7), and illicit/recreational drugs (AOR: 1.8, 95%CI: 1.1 – 2.7). In addition, living in urban areas, income below the federal poverty level, and not being married were significant predictors of unintended pregnancy. Study 3: Our SR with MA included eight observational studies (N=38,520 women). Pooled findings indicated that illicit and recreational drugs use during the preconception period was significantly and positively associated with the likelihood of unintended pregnancy (pooled odds ratio (POR)=1.84, 95% CI: 1.4-2.4).

Conclusion: Findings of our two studies in a large representative sample of US women suggest that substance and polysubstance use during the preconception period significantly increases the likelihood of unintended pregnancy. Consistent with these results, the pooled findings of our SR with MA indicated a significant and positive association between the use of illicit and recreational drugs and the risk of unintended pregnancy. Collectively, these findings support a potential causal link between preconception substance use and subsequent risk of unintended pregnancy. These findings highlight the need for tailored screening, educational, and treatment programs and integrated family planning services to help reduce both substance use and unintended pregnancy among women of childbearing age.