The association between the legalization of recreational marijuana and both small for gestational age births and NICU admissions in Colorado.

OBJECTIVE

To determine the association between recreational marijuana legalization and both small for gestational age (SGA) births and neonatal ICU (NICU) admissions in Colorado.

STUDY

DESIGN

Using interrupted time series analysis, we compared the incidence of SGA births and NICU admissions pre-/post-recreational marijuana legalization. Secondary analysis adjusted for marijuana outlet density (MOD) in maternal county of residence.

RESULTS

We analyzed 269,922 mother-infant dyads. SGA birth risk dropped 7% immediately post-legalization (p = 0.04), but there was no slope difference between cohorts. SGA birth risk for high MOD dyads was 1.4x that of dyads with no outlets (p < 0.001) and 1.2x that of low MOD dyads (p = 0.002). There was no immediate effect on NICU admission risk, but the slope increased 1%/month post-legalization (p < 0.001) including a 1%/month increase for low MOD and 3%/month for high MOD dyads.

CONCLUSIONS

Incidence of SGA births in Colorado did not change following recreational marijuana legalization. NICU admissions increased post-legalization.