Reported Cannabis Use in Pregnancy Dropped After New Mexico Legalization | Research

The takeaway

Contrary to expectations, reported prenatal cannabis use decreased after recreational legalization in New Mexico, though infants with prenatal exposure continued to have worse birth outcomes including lower weight, length, and Apgar scores.

Obstetricians, neonatologists, and cannabis legalization researchers

Reported prenatal cannabis use decreased from 33.8% to 22.8% after legalization

What the researchers found

Reported prenatal cannabis use significantly decreased from 33.8% (Epoch 1: pre-legalization) to 22.8% (Epoch 2: post-legalization). The decrease likely reflects changes in screening practices, the COVID-19 pandemic, or delayed commercialization rather than actual decreased use. Regardless of epoch, infants exposed to cannabis had smaller birth weight, length, head circumference, and lower Apgar scores.

Why it matters

This is one of the first studies to examine how recreational legalization actually affected reported prenatal cannabis use. The counterintuitive decrease highlights the complexity of measuring cannabis use in pregnancy and the potential impact of policy changes on screening and disclosure.

The numbers in context

Epoch 1: 403 cases out of 1,191 (33.8%). Epoch 2: 86 cases out of 378 (22.8%). Significant decrease post-legalization. PCE infants in both epochs: lower birth weight, length, head circumference, and Apgar scores at 1 and 5 minutes. More C-sections in PCE group.

How the study worked

Retrospective cohort comparing two epochs at a New Mexico hospital: pre-legalization (Jan 2019-Mar 2021, n=1,191) and post-legalization (Nov 2021-Nov 2022, n=378). Cases identified by documented self-report or positive toxicology test. Birth outcomes compared between exposed and unexposed groups.

What this study cannot tell us

Single hospital. Unequal epoch sizes (1,191 vs 378). COVID-19 pandemic overlapped with both epochs. Changes in screening practices were not tracked. Cannot distinguish between actual use changes and reporting/detection changes. Short post-legalization period.

How to read the evidence

Single-center retrospective study with significant design limitations including unequal epoch sizes and pandemic overlap.

When this study was published

2024 study using 2019-2022 data

The bigger picture

The finding that legalization did not increase reported prenatal use (and may have appeared to decrease it) does not necessarily mean actual use decreased. Changes in screening protocols, provider attitudes, and patient disclosure behavior around legalization may explain the paradox.

Questions still open

Did screening practices change after legalization? Is the apparent decrease in prenatal cannabis use an artifact? Would biomarker-based studies show different trends? How long after commercialization do use patterns stabilize?

Common questions

Did cannabis legalization increase use during pregnancy?

Surprisingly, no. In this New Mexico study, reported prenatal cannabis use decreased after recreational legalization. However, this may reflect changes in screening practices rather than actual use.

Does prenatal cannabis affect birth outcomes?

Yes. In both pre- and post-legalization periods, cannabis-exposed infants had lower birth weight, length, head circumference, and Apgar scores, and were more likely to be delivered by C-section.

Read the original research

The impact of recreational cannabinoid legalization on utilization in a pregnant population.

Frontiers in public health, 12, 1278834

View on PubMed ↗Publisher’s paper ↗

Citation

Torres, Jacob; Miller, Colton; Apostol, Michael; Gross, Jessica; Maxwell, Jessie R. (2024). The impact of recreational cannabinoid legalization on utilization in a pregnant population.. Frontiers in public health, 12, 1278834. https://doi.org/10.3389/fpubh.2024.1278834