Concordance and discordance between maternal and newborn drug test results

Pre-natal and post-natal screening and testing in neonatal abstinence syndrome

The way we enact screening for substance use during pregnancy within our healthcare systems can work by decreasing stigma, promoting engagement, and supporting people with reaching the end of their pregnancy in a manner where the newborn can be well supported. The way we enact biochemical specimen toxicology testing for substance use during pregnancy and in newborns contributes to increased stigma, disengagement from care, and potential continuation of uncontrolled substance use up until delivery such that the newborn may not be able to be well supported in the family environment. These effects are inequitably distributed, leading to worse outcomes for families of color and families living in poverty. Serial screening with a validated questionnaire starting at the first prenatal visit and continuing through the delivery hospitalization should occur and be followed up with service connections and substance use disorder diagnosis and treatment. Newborn toxicology testing as a diagnostic tool for risk of withdrawal or the etiology of potential withdrawal symptoms represents a failure in the effectiveness of compassionate communication by healthcare providers with the birthing person. Given the current level of evidence of clinical utility and the inequitable consequences specific to these tests, they are rarely needed.

Biological Testing and Interpretation of Laboratory Results Associated with Detecting Newborns with Substance Exposure

BACKGROUND

Substance use during pregnancy is common, as is biological testing that is intended to help identify prenatal exposures. However, there is no standardized requirement for biological testing with either maternal or newborn specimens, nor is there standardization related to when testing occurs, how frequently testing occurs, what specimen(s) to test, what substances to test for, or how to perform testing.

CONTENT

We review common specimen types tested to detect maternal and newborn substance exposure with a focus on urine, meconium, and umbilical cord tissue. We also review common analytical methods used to perform testing, including immunoassay, and mass spectrometry platforms. Considerations regarding the utilization of testing relative to the purpose of testing, the drug analyte(s) of interest, the specific testing employed, and the interpretation of results are emphasized to help guide decisions about clinical utilization of testing. We also highlight specific examples of unexpected results that can be used to guide interpretation and appropriate next steps.

SUMMARY

There are strengths and limitations associated with all approaches to detecting substance exposure in pregnant persons as well as biological testing to evaluate a newborn with possible substance exposure. Standardization is needed to better inform decisions surrounding evaluation of substance exposures in pregnant people and newborns. If biological sampling is pursued, testing options and results must be reviewed in clinical context, acknowledging that false-positive and -negative results can and do occur.

Maternal and infant cannabis testing and associated birth outcomes

OBJECTIVES

The objective of the study was to determine any identifiable clinical utility of the practice of universal maternal and infant tetrahydrocannabinol (THC) testing at the time of birth.

METHODS

This was cross-sectional, retrospective cohort study comparing the following birth outcomes in relation to maternal and infant tetrahydrocannabinol (THC): APGAR scores, cord gases, NICU admission and need for immediate resuscitation. All births at the University of Maryland Medical Center between January 1, 2018 and December 31, 2020 were reviewed. Those that had either maternal or infant test results missing were excluded. Statistical analysis was performed using STATA v27. Birth outcomes were adjusted for gestational age at delivery and tobacco use. Infant resuscitation was considered the need for any respiratory support.

RESULTS

A total of 4260 maternal/infant pairs were included. Of these, 314 (7.4%) birthing parents and 161 (3.8%) of infants tested positive for THC. Of the birth parents who tested positive for THC, 51.3% of their infants also tested positive for THC. Maternal/infant pairs that both tested positive for THC had the lowest need for immediate resuscitation and Neonatal Intensive Care Unit admission. Cord gases and APGAR scores were similar between the groups. Birth parents who tested positive for THC delivered infants at an earlier gestational age (37w6d v 38w5d, p = 0.001) and lower mean birth weight (2690gm v 3061gm, p = 0.001) than those who tested negative even after adjusting for confounders. When limited to only term births and broken down by weeks completed gestation, the mean birth weights were lower for every week in those who tested positive for THC versus those who tested negative.

CONCLUSIONS

Our study shows that maternal and neonatal testing for THC at the time of birth is not predictive of important neonatal outcome parameters. Therefore, even though it is likely that there are some effects of in utero THC exposure on the neonate, we did not find any clinical benefits that would justify routine maternal and/or infant testing for THC at the time of birth.

Drug Testing of Pregnant Patients

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