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.