Incidence of Newborn Drug Testing and Variations by Birthing Parent Race and Ethnicity Before and After Recreational Cannabis Legalization.

Importance: Thirty-seven US states and the District of Columbia mandate reporting newborns with suspected prenatal substance exposure to the state, and punitive policies that link prenatal substance exposure to newborn drug testing (NDT) may lead to disproportionate reporting of Black parents to Child Protective Services. The impact of recreational cannabis legalization on racial disproportionality in NDT is unknown. Objectives: To examine variations in the incidence and results of NDT by birthing parent race and ethnicity, variables associated with variation, and changes after statewide legalization of recreational cannabis. Design, Setting, and Participants: This retrospective cohort study was conducted from 2014 to 2020 with 26 366 live births to 21 648 birthing people who received prenatal care at an academic medical center in the Midwestern United States. Data were analyzed from June 2021 to August 2022. Exposures: Variables included birthing parent age, race, ethnicity, marital status, zip code, insurance type, prenatal and newborn diagnoses codes, and prenatal urine drug test orders and results. Main Outcome and Measures: The primary outcome was an NDT order. Secondary outcomes were substances detected. Results: Among 26 366 newborns of 21 648 birthing people (mean [SD] age at delivery, 30.5 [5.2] years), most birthing parents were White (15 338 [71.6%]), were non-Hispanic (20 125 [93.1%]), and had private insurance coverage (16 159 [74.8%]). The incidence of NDT ordering was 4.7% overall (1237 newborns). Clinicians ordered more NDTs for Black compared with White newborns (207 of 2870 [7.3%] vs 335 of 17 564 [1.9%]; P < .001) when the birthing parent had no prenatal urine drug test, a presumably low-risk group. Overall, 471 of 1090 NDTs (43.3%) were positive for only tetrahydrocannabinol (THC). NDTs were more likely to be positive for opioids in White compared with Black newborns (153 of 693 [22.2%] vs 29 of 308 [9.4%]; P < .001) and more likely to be positive for THC in Black compared with White newborns (207 of 308 [67.2%] vs 359 of 693 [51.8%]; P < .001). Differences remained consistent after state recreational cannabis legalization in 2018. Newborn drug tests were more likely to be positive for THC after legalization vs before legalization (248 of 360 [68.9%] vs 366 of 728 [50.3%]; P < .001) with no significant interaction with race and ethnicity groups. Conclusions and Relevance: In this study, clinicians ordered NDTs more frequently for Black newborns when no drug testing was done during pregnancy. These findings call for further exploration of how structural and institutional racism contribute to disproportionate testing and subsequent Child Protective Services investigation, surveillance, and criminalization of Black parents.

The fat-like cadherin CDH-4 acts cell-non-autonomously in anterior-posterior neuroblast migration.

Directed migration of neurons is critical in the normal and pathological development of the brain and central nervous system. In Caenorhabditis elegans, the bilateral Q neuroblasts, QR on the right and QL on the left, migrate anteriorly and posteriorly, respectively. Initial protrusion and migration of the Q neuroblasts is autonomously controlled by the transmembrane proteins UNC-40/DCC, PTP-3/LAR, and MIG-21. As QL migrates posteriorly, it encounters and EGL-20/Wnt signal that induces MAB-5/Hox expression that drives QL descendant posterior migration. QR migrates anteriorly away from EGL-20/Wnt and does not activate MAB-5/Hox, resulting in anterior QR descendant migration. A forward genetic screen for new mutations affecting initial Q migrations identified alleles of cdh-4, which caused defects in both QL and QR directional migration similar to unc-40, ptp-3, and mig-21. Previous studies showed that in QL, PTP-3/LAR and MIG-21 act in a pathway in parallel to UNC-40/DCC to drive posterior QL migration. Here we show genetic evidence that CDH-4 acts in the PTP-3/MIG-21 pathway in parallel to UNC-40/DCC to direct posterior QL migration. In QR, the PTP-3/MIG-21 and UNC-40/DCC pathways mutually inhibit each other, allowing anterior QR migration. We report here that CDH-4 acts in both the PTP-3/MIG-21 and UNC-40/DCC pathways in mutual inhibition in QR, and that CDH-4 acts cell-non-autonomously. Interaction of CDH-4 with UNC-40/DCC in QR but not QL represents an inherent left-right asymmetry in the Q cells, the nature of which is not understood. We conclude that CDH-4 might act as a permissive signal for each Q neuroblast to respond differently to anterior-posterior guidance information based upon inherent left-right asymmetries in the Q neuroblasts.