Validation of simple dichotomous self-report on prenatal alcohol and other drug use in women attending midwife obstetric units in the Cape Metropole, South Africa

Background: This paper examines the degree of agreement among simple dichotomous self-report, validated screening results, and biochemical screening results of prenatal alcohol and other drug use among pregnant women. Method: Secondary analysis was conducted on a cohort of pregnant women 16 years or older, presenting for prenatal care in the greater Cape Town, South Africa. Dichotomous verbal screening is a standard of care, and pregnant patients reporting alcohol and other drug use in dichotomous verbal screenings were asked to engage in screening using the Alcohol Smoking and Substance Involvement Screening Test (ASSIST) and urinalysis. Results: Significant agreements between dichotomous and ASSIST scores were observed (K = 0.73–0.76). A higher rate of self-reported (36.9%) alcohol use was detected, relative to urine screening (19.6%) with a predictive value of 34.9; while underreporting of illicit substance use was observed (3.6% self-report vs. 8.8% urine screening) with an overall predictive value of 50.0. Conclusion: Dichotomous verbal screening was considered valid after comparison with the ASSIST; however, combined use with urine screenings can be recommended especially for identifying illicit substance use in order to accurately detect alcohol and other drug use in pregnancy, so that women can be identified and referred for appropriate interventions where needed.