Rapid urine screening for ethyl glucuronide from pregnant women as a tool for detecting prenatal alcohol exposure

Background An increasing prevalence of alcohol consumption is a major public health problem, which has also led to an increasing number of children who have been prenatally exposed to the toxic effects of ethanol. However, obtaining reliable information on prenatal alcohol exposure through maternal self-reports has proved difficult. Aims Our aim was to evaluate the potential for rapid screening test for measuring ethyl glucuronide (EtG), a specific alcohol metabolite, from urine samples of pregnant women. Methods Five hundred five urine samples of pregnant women were collected anonymously from five prenatal units in two Finnish cities: a tertiary specialist antenatal clinic for pregnant women with problematic substance use (HAL), a regular hospital antenatal clinic (LCH = Lahti Central Hospital), a prenatal screening unit and two community maternity clinics (USR = user self-recruiting units). All samples were screened using rapid EtG test strips, and all positive, uncertain, and randomly selected negative samples were confirmed by quantitative analyses. The samples were also screened for cotinine and use of cannabis. Results In this material an EtG cut-off of 300 ng/mL suggesting heavy alcohol drinking was exceeded by 7.4% (5/68) of the samples in the HAL clinic, 1.9% (4/202) in LCH, and 0.9% (2/225) in USR. A cut-off of 100 ng/mL was exceeded by 17.6% (12/68) of samples from HAL, 7.5% (16/212) from LCH, and 6.7% (15/225) from USR. Based on confirmatory quantitative analyses, there were no false negatives nor false positives in rapid EtG screening. However, 57 (11.3%) of test results were classified as uncertain. In these cases, confirmation by quantitative analyses resulted in 56.1% rate of positive values. 73% of the samples with EtG > 300 ng/mL showed positive cotinine results suggesting smoking co-occurring with alcohol intake. Conclusions Rapid EtG tests may be an easy and inexpensive method, which may improve the possibilities for screening alcohol use among pregnant women during routine prenatal visits. Quantitative EtG analyses are recommended to confirm screening positive and uncertain cases. Trial registration NCT04571463 Date of Registration 11/05/2020.