Historical and clinical factors associated with positive urine toxicology screening on labor and delivery

Objective: Illicit drug use in pregnancy may lead to adverse outcomes. Although the American College of Obstetricians and Gynecologists recommends that all pregnant women be screened for substance use by questionnaire or conversation, it remains unclear how well these methods identify women with illicit drug use. Drug use may also be suspected based on clinical complications, such as fetal demise or placental abruption. There are currently no formal recommendations to guide targeted laboratory testing in women perceived to be at risk based on historical or clinical factors. Our objective was to determine which historical and clinical factors are associated with positive urine toxicology screens in women admitted to labor and delivery. Study design: Historical cohort study of all women admitted to labor and delivery at our county hospital over a 5-year period (2010-2014). All patients underwent historical and clinical risk assessment and women perceived to be at increased risk of illicit drug use and who consented to testing had urine toxicology performed. We conducted a detailed chart review on all women with a positive test during this 5-year period and compared them to all women with a negative test in 2014, reporting values significant at a p-value of <0.05. Results: Amongst the 19,604 admissions during this period, 850 women underwent urine toxicology testing, accounting for 4.8% of all admissions. We compared the 83 women who tested positive for illicit drugs (9.8% of all women tested) to the 179 women who tested negative in 2014. Historical drug use was the factor most strongly associated with a positive test. Other historical and demographic factors associated with a positive test included single relationship status, lack of employment, lack of high school education, nulliparity and history of a prior sexually-transmitted or blood-borne infection. Regarding clinical risk factors, maternal medical complications were not associated with a positive test, and obstetrical complications, like preterm labor, were associated with a negative test. Conclusions: A positive urine toxicology test was most strongly associated with maternal historical factors, especially known drug use. No clinical risk factor was associated with a positive test. The implications of our findings in guiding targeted laboratory testing are discussed. (C) 2018 Elsevier B.V. All rights reserved.